Can a custodial parent with joint legal custody sue someone the child was in an auto accident with when the father does not agree?

If the mother is already the non-custodial parent, then the custodial father already has custody. If the question is meant to ask if the mother can give up her parental rights, then you would need to petition the court.

he needs to file for custody

It's likely, but I don't think that you could legally demand custody. You could work out some arrangements with the custodial step father and the biological father concerning visits and vacations, but you will still need a court order that gives you custody.

No. If the mother has full custody, the father must pay child support to the mother who is supporting the child. Put simply, the non-custodial parent pays child support to the parent who does have custody.If the custodial parent makes significantly more than the non-custodial parent, the court will not order the non-custodial parent to pay the custodial parent. There are formulas for each state and county that the courts follow. There are also circumstances that do not follow typical guidlines.

He can request custody or a visitation order if he is the father of the child. At the same time you should petition to remain the custodial parent and request a child support order.He can request custody or a visitation order if he is the father of the child. At the same time you should petition to remain the custodial parent and request a child support order.He can request custody or a visitation order if he is the father of the child. At the same time you should petition to remain the custodial parent and request a child support order.He can request custody or a visitation order if he is the father of the child. At the same time you should petition to remain the custodial parent and request a child support order.