not sure but my understanding is that it all depends if he dies with a will written/properly done. If that will has his stuff going to someone other than his children....then that's that. A fight might be able to be made for some of it -- lawyer.

However, if he was court ordered to pay child support and never did pay it all you might still be able to get that from him. Again -- ask attorney.

If he has a will, the will controls, except some states have statues that require a certain portion go to the surviving spouse no matter what the will says.

Without a will, in most states, the surviving spouse automatically inherits. Kids are out of luck.

Your question is state specific and you should consult a lawyer familiar with the laws of the state in which your ex resides.