I'll only discuss your debt.
You'll need to sue him in small claims, but that's only about 20% of your work.
You'll likely prevail in a small claims suit against him, based on their divorce decree and your other documentation.
But, you'll only walk out with a judgment.
You'll then need to file the judgment with the clerk. That's another 10%.
Then you'll have to try and enforce it.
That's The remaining 70%, and the hardest part.
The others will be required to bring their own cases in the same manner, small claims.
Do you see the picture?
Mom, no doubt, divorced this creature for many reasons. One occurs to me, deadbeat.
Do you really think you'll ever see a dollar of the $750?
Be forewarned, filing a small claims case costs money, paid up front (filing fees, service fees, court costs).
Sure, you prevail, the other guy must pay you back, but you've spent more money.
So, if it costs $100, $200 to bring the lawsuit, add that to the $750, and he owes you $1,000 now.
But, you don't get cash, just a "he owes you"!
Good luck, I'd cut my losses.
You make your choice.
Now, you could sue mother.
But, who sues their mother?
I'd never do that, and I'm a cutthroat lawyer. Lawyers do have limits, incidentally. :yes:
Besides, mom made good her portion.
Yeah, you could argue she's responsible for suing him, and go after her.
But, what kind of creature sues their mom?
My advice, forget it, and move on.
Or, go to small claims, and really end up frustrated and losing more money.