[jyl]

At a minimum, SIL should separate her finances from Chuck. Any joint bank accounts, joint credit accounts, should be closed. Chuck will go BK and hopefully she won't go BK and have her credit wiped out by him. I guess if she lives in a community property state that might be hopeless, I don't know.

The next thing she should do is take control of the finances. Chuck gets an allowance from her and that's all. No credit card, no checkbook.

What she should really do is divorce him, and the sooner the better.

Finally, as long as I'm spouting off advice that I know you have already thought of and that your SIL probably already knows but is unable/unwilling to act on - sigh - here is something more speculative . . .

. . . I speculate your SIL has serious insecurity and low self-worth, leading her to subject herself to bums like Chuck because no-one better will have her (she thinks). I further speculate (speculating wildly here) a part of the reason is because she sees herself as fat and unattractive (you said "big"). Dumping Chuck but remaining insecure/low self-worth just sets her up for the next Chuck.

Ideally, like "Dear Santa can I have a pony too" ideally, she would dump Chuck and fix her self-image problems at the same time.

Sorry to read your post. She sounds like a good person who is headed for a disaster.