(((((liesagain))))
As far as the child goes you may not have any legal rights also if you do keep the child it would probably keep you tied to the dad...
I am sure the child is worth a fight to keep him win or loose he would know that at least you did try and it could be a boost for his self esteem. Are your children related to him? I am sure that could carry some weight in court.
Hang in there...