If he had invented this thingy while they were together, they couldn't really do much as this thingy was made after the divorce and the settlement had gone through.
If he didn't pay child support and he wasn't working during the time or didn't have money when they had separated, she still wouldn't be entitled to anything.
And if he did have to pay out because of this, then he should only pay the amount of child support she would have been entitled to only, nothing more.
Advancement in the company?
I wish.