You can sue a family member yes. Some states, not sure about OH yet, do not permit a spouse to sue the other, that is all. I live in Ohio, but I am assuming it is a non spouse.
I am also assuming the amount far exceeds Ohio small claims jurisdiction, which is 3 grand.
Sure, an attorney "may " take it on contingency, but the problem is collecting to pay him. Sure a Judgment is good in Ohio I think for 15-20 years, but to pay him, you need to collect.
Does the person have any assests attachable? A Bank account that can be garnished, wages that can be garnished?
I also assume such a large amount was in Writing? Right?

