Real talk. Depending on what state he's in, he might have a problem on his hands.
Paying Child Support for a Non-biological Child | LegalMatch
As noted above, a family court can order a non-biological parent to pay child support in certain situations. The person will need to be a legal or equitable parent. Look to your state’s child support guidelines for more information about when this could apply. Some factors that could weigh into this decision include the following:
You financially supported the child for a significant amount of time;
You emotionally supported the child for a significant amount of time;
You lived with the child and other parent; and
You helped make important parenting decisions, like where the child would go to school or what medical treatment the child would receive.
All of this could support a case for equitable paternity if you are not a biological or legal parent of the child. This can make it difficult to avoid child support payments mandated by court order. However, keep in mind that this will also support a case for you to have custody rights over the child, which means you could fight for shared custody or visitation rights.
You can also attempt to establish someone else’s biological paternity as a defense to making these payments. However, say you acted as a father figure to a child by exhibiting all or some of the traits discussed above. Even if you track down the biological father, if they were never involved in the child’s life then the court may still order you to make the child support payments if you separate from the mother.