Raise the cash cow money and have the foster parents adopt them.
My little brother did this. He and his wife started out as foster parents and they loved the check the baby brought. They were made foster parents when the baby was a day old. My brother and his wife are the only parents that child has ever known.
The mother had 3 kids, by 3 different fathers, was a drug abuser and alcoholic who couldn’t and wouldn’t take care of the kids. All 3 were in different foster homes.
Long story short, my brother and his wife legally adopted ALL THREE to keep the kids together.
Today they’re one happy family.