Social Security Survivor Benefits?

My ex claimed a child when married to a now ex of his. The child is not his, but he has been receiving Social Security payments for the child along with his Social Security payments. What happens to these payments once he passes and who is entitled to collect on ex's Social Security as ex wife? I had over 10 years married to him. Will the other mom collect even though the child is not his? This child was not legally adopted by him, he just went along with saying it was his child. We all live in Virginia.