A couple days ago Mr. Waffle called me from work and asked if I wanted to go back East to see his sister with him. She was having surgery, and offered to pay for our tickets so he could help take care of her.

I immediately said yes, but later on realized this sister and I don't really have much in common, she lives in a really tiny place, and is a pretty bad germaphobe, along with not liking fat people very much.

Last night, Mr. Waffle said his sister didn't think she'd be able to accommodate us both, and was really secretive about what kind of surgery she's having—apparently it's cosmetic, and she doesn't want the rest of the family knowing about it. Truth be told, I was relieved to be off the hook, but worried because this sounds very out-of-character for her.

Just a few minutes ago, Mr. Waffle texts and says his sister feels bad that I can't come, and she wants to help us spend a few days in Cancun as a thank-you for helping her.

This just seems really strange for her. Having cosmetic surgery, keeping it a secret from the family, being overly generous with money... Their whole family has depressive issues, and Mr. Waffle suffers from OCD and alcoholism (we're still dealing with his crush on my friend, that's a whole other kettle of fish). I'm worried she's having some issues, but we're not close enough for me to ask. What should I do?