Being family, adopted or blood, gives no one special priviledges to abuse you and wipe their feet on your soul. I know family. I am adopted. I found my biological family. I know the dysfunctions of both. I have two biological sons. One I cannot associate with currently for my own self-defense, my own protection. You should do what is right, always what is right, no matter what the consequence, no matter what "family" you lose, IMO. You have my sympathies with your situation and I hope you and your nephew can come through the other side with little damage.