I disagree that the BF needs to address this with his family. As long as he's supportive of the OP and backs up her decision to not buy presents (or nice presents) for the sister, I think he's doing just fine. As someone who has a mother with "issues" I've had to say "That's the way she is" when mom behaves badly. Me, bro and sis just ignore her, while SIL will get very upset. We do our best to encourage SIL to ignore mom's outbursts and walk away. That's what we do. We do not placate mom, give in to her, etc. We will leave, walk away, ignore her, etc. until she decides to act "normal" again. She's been told several times about her behavior but she can only change herself. In the OP's case, DF can't make his sister do anything. Yes, he CAN speak speak to her and explain what she did was offensive, and ask for an apology or something like that. But honestly, I don't think he should be put in this position and I doubt she will change. I say as long as BF has the OP's back and supports her in how she decides to go from here, he is good in my book. Unless the Sis is doing other things that send out a signal that she's out to get the OP and hurt her, I'd chalk this up to SS/cluelessness and mark her as someone not worth spending time and money on because she doesn't know how to be gracious or appreciate nice things.