This is the advice provided by the Watchtower.
Kingdom Ministry August 2002 p.3 Display Christian Loyalty When a Relative Is Disfellowshipped
“4 What about speaking with a disfellowshipped person? While the Bible does not cover every possible situation, 2 John 10 helps us to get Jehovah’s view of matters: “If anyone comes to you and does not bring this teaching, never receive him into your homes or say a greeting to him.” Commenting on this, The Watchtower of September 15, 1981, page 25, says: “A simple ‘Hello’ to someone can be the first step that develops into a conversation and maybe even a friendship. Would we want to take that first step with a disfellowshipped person?”
Even though your family may be disobeying the Governing Body in this regard, they still do not associate with your uncle as a normal family would. I can assure you that it is heartbreaking for your uncle to be treated that way.