JW's must shun and have absolutely nothing to do with children, parents, grandchildren, grandparents, siblings, aunts, uncles, cousins, ... all family members and friends who leave the Watchtower Society by voluntary resignation or force, - i.e. disfellowshipping, excommunication (subject to very limited exceptions) 
Millions of families and loving relationships have abruptly ended since the Watchtower's shunning policy was instituted in 1952. 
Although in the beginning it was hoped that disfellowshipping would keep immoral persons out of the organization, it soon became a tool to command loyalty and silence all who disagree. In 1981, it became a sin to disagree with the Watchtower Society or leave the organization for any reason, - even if a person was not immoral. Watchtower magazine, Sept 15, 1981, p 23, par 14-16
Shunning is not a matter of conscience or a voluntary choice of individuals. It is required by the Watchtower as a condition of being a member of 'God's organization'. Those who disobey can be disfellowshipped and shunned for breaking Watchtower laws, - i.e. 'God's command' as stated in the following Watchtower quote. 
'What if we have a relative or a close friend who is disfellowshipped? Now our loyalty is on the line, not to that person, but to God. Jehovah is watching us to see whether we will abide by his command not to have contact with anyone who is disfellowshipped. ... Consider just one example of the good that can come when a family loyally upholds Jehovah’s decree not to associate with disfellowshipped relatives. A young man had been disfellowshipped for over ten years, during which time his father, mother, and four brothers “quit mixing in company” with him. At times, he tried to involve himself in their activities, but to their credit, each member of the family was steadfast in not having any contact with him. After he was reinstated, he said that he always missed the association with his family, especially at night when he was alone. But, he admitted, had the family associated with him even a little, that small dose would have satisfied him. However, because he did not receive even the slightest communication from any of his family, the burning desire to be with them became one motivating factor in his restoring his relationship with Jehovah. Think of that if you are ever tempted to violate God’s command not to associate with your disfellowshipped relatives.' Watchtower magazine, April 15, 2012, Article: 'Betrayal—An Ominous Sign of the Times!', par 16, 17
Notice how the Watchtower uses the name of God when referring to themselves! They trick Jehovah's Witnesses into believing a 'reinstated' person is 'restoring his relationship with Jehovah', when in fact he is 'restoring his relationship with the Watchtower'. One can have a relationship with God and belong to any religion or none at all. A relationship with 'Jehovah', does not depend upon membership in the Watchtower Society or any religious affiliation. 
Also notice that shunning disfellowshipped people is not just a matter of conscience. It is required by the Watchtower. They say it's 'God's command'. At the end of the above quote they say, 'Think of that if you are ever tempted to violate God’s command not to associate with your disfellowshipped relatives.' [bold type added] 
In 1981, the Watchtower made it a serious sin to leave their organization. Since then anyone who leaves for any reason is labeled a 'wrong doer' who must be shunned. Here's what the 1981 Watchtower says.
'14 One who has been a true Christian might renounce the way of the truth, stating that he no longer considers himself to be one of Jehovah’s Witnesses or wants to be known as one. When this rare event occurs, the person is renouncing his standing as a Christian, deliberately disassociating himself from the congregation. The apostle John wrote: “They went out from us, but they were not of our sort; for if they had been of our sort, they would have remained with us.”—1 John 2:19.
15 Or, a person might renounce his place in the Christian congregation by his actions, such as by becoming part of an organization whose objective is contrary to the Bible, and, hence, is under judgment by Jehovah God. (Compare Revelation 19:17-21; Isaiah 2:4.) So if one who was a Christian chose to join those who are disapproved of God, it would be fitting for the congregation to acknowledge by a brief announcement that he had disassociated himself and is no longer one of Jehovah’s Witnesses.
16 Persons who make themselves “not of our sort” by deliberately rejecting the faith and beliefs of Jehovah’s Witnesses should appropriately be viewed and treated as are those who have been disfellowshipped for wrongdoing.' Watchtower magazine, Sept 15, 1981, p 23, par 14-16
Double Standards. The Watchtower fights for freedom of religion so they can spread their unpopular beliefs. At the same time they shun members who resign or join a different religion. See Freedom of Thought, Conscience, and Beliefs
Religious Persecution of Jehovah's Witnesses who leave the Watchtower
2013 Convention of Jehovah's Witnesses talk Shun Your Family
The name Jehovah was invented by the Christian scholars in the 13th century and used extensively in the NWT translation of Jehovah's Witnesses. At the same time Jehovah's Witnesses blast Christendom for "hiding the name of God" by replacing the name "Jehovah" in the Bible with "the Lord".
Disfellowshipping and shunning began in 1952. Since then millions of families have been torn apart by the Watchtower's shunning requirement.
The secret Watchtower rule book, Shepherd the Flock of God, confirms the punishments for violating the Watchtower's shunning requirement.
Jehovah's Witnesses believe it's appropriate for the Watchtower to tell the world what God's commands are and to enforce them on behalf of God. They believe the Watchtower is God's 'messenger' and 'prophet'. However they are mistaken. The Watchtower's predictions from 1889 to 2008 have failed, proving that they are not in communication with God.
Since the historical record of the Watchtower proves they are a modern day 'false prophet', the use of God's name when referring to their own 'commandments' or 'rules', deceives millions of currently active Jehovah's Witnesses and interested persons who are totally unaware of the Watchtower's track record. Hiding the truth from young and new Jehovah's Witnesses fits in nicely with their 'Theocratic War' doctrine. Read Watchtower Theocratic Warfare Quotes about why it's ok to mislead people to protect 'God's organization'. As you read what the Watchtower says, ask yourself if they have any integrity, conscience, or compassion. Millions of Jehovah's Witnesses are working hard for the Watchtower at their own expense because they believe they are working for God. Thanks to loyal Jehovah's Witnesses, the Watchtower continues to accumulate cash, real estate, and financial assets.
Although Jehovah's Witnesses believe the Watchtower is God's prophet and messenger, on rare occasions the Watchtower has disclaimed having any divine inspiration.
Why do Jehovah's Witnesses obey the Watchtower when the truth is readily available? See Mind Control
The Watchtower's shunning policy appears to be an outright rejection of the teachings of Jesus in Matthew 5:46,47 where he said, 'If you love those who love you, what reward will you get? Are not even the tax collectors doing that? And if you greet only your own people, what are you doing more than others? Do not even pagans do that?'
Apostasy began immediately as soon as Jesus died. In 2 Thessalonians 3, the Apostle Paul admonishes early Christians to 'obey' him and other leaders in the church. He also 'commands' them twice not to associate Christians who are 'idle' (lazy) and 'disruptive', so that they might become ashamed. This is interesting because in Acts 5:29, 'Peter and the other apostles replied: "We must obey God rather than human beings!' Read more about 2 Thessalonians 3
Luke 12:51-53; 'Do you think I came to bring peace? No I tell you, but division.'