Ending friendship may have familial repercussions

DEAR HARRIETTE: I have a friend I’ve been thinking about cutting ties with for a while now, but I feel conflicted about it. I’ve noticed that the way he treats people, including me, is questionable. Whenever I need help or support, he seems to be conveniently busy or unavailable, yet he expects everyone else to drop what they’re doing to be there for him. The way he speaks to people can be rude and dismissive, and he often communicates in a way that feels condescending. On top of that, he lies a lot, and it’s hard to tell when he’s being truthful. It’s exhausting to be around someone like that, and I don’t feel like the friendship adds anything positive to my life anymore. The problem is that he’s also close with my sister, and I don’t want to create unnecessary tension or awkwardness between us if I stop talking to him.