Deciding to refrain from hanging out with someone whose behavior is destructive and refuses to change is understandable as everyone has the right to protect themselves from harmful infuences.
Deciding to shun a family member or close friend absolutely and without mercy because they have doubts about the GB's claim of being hand selected by Jesus himself along with any other of WT's loose intepretive rules to do with personal choice is not only unscriptural but downright wrong!