Responses
First of all, I think the woman he is indebted to will be really thrilled to know he is sleeping with her son - I'm sure he has done it for her. What is more important, if you know that someone has some feelings for you, you should set some boundaries. It's bad for you and for the other person if you won't cut it off clearly.

Yep, You know that your brother lusts after you, but you still get drunk and pass out when it's just the two of you. I really don't understand this kind of behavior.
We know what kind of person his brother is, so it was predictable.