Legally, yes, you could be entitled to some of her income depending on the details of your case. Let the caseworker (or judge) know he's got other sources of money and they'll fight to get it for you. The State's receive Federal money proportional to all the child support mothers collect, so the child support people are incented to boost up support orders. You and the State both come out ahead and he pays more!

Is she a tenant with a signed lease? If not, then no the money she's providing him is not considered income.

Just like if you had a boyfriend that was giving you money, that wouldn't be considered income. The only exception to that is when an ex-spouse is receiving alimony and then lives with a new person...that can lessen the money they receive from the other person.

But if you're not paying him any alimony...that wouldn't apply. Basically, her income has nothing to do with you and your ex's agreement.