What am I supposed to say?

I may have mentioned that I have a tough time picking up on and processing social cues. I’m working on it. So when people tell me their problems that I think are their own fault, that’s obviously not what they want to hear. I have no idea what a normal person would say to something like this for instance: “My husbands son lives in a house that is on the same electrical line as ours. I pay the bill even though he is supposed to pay half because he knows we don’t want our electric shut off.” My impulse is to tell her to kick the little brat out. A normal person would commiserate with her. I guess. Can you tell me some things I could say that a nice person would say?