Support from In-Laws

For the 13 years of our marriage, my husband has received a large check from his parents every month. It has always been made out to him except in the past several months part of the check was made out to the bank that holds our mortgage to ensure our mortgage was paid because my husband is an alcoholic and they don’t trust he is paying the mortgage. They don’t like me because I don’t enable their son and they know we are considering a divorce. Can I sue him for alimony/child support for that money? I can prove that he has been getting it regularly because it got deposited in our joint bank account. Does it matter if it is from an inheritance/trust fund? I don’t know for sure because they are very secretive. Thank you.

Yes, that recurring check from his parents is considered income for support purposes.

It matters from an equitable distribution standpoint if the funds are coming from an inheritance (then it is considered separate property), but it can be considered as income for support.