I have full custody of my cousinds baby for about 2 years and the father at the time left me with the baby so that he can stabalize himself, but he just abandoned the child.He is now seeking custody of the child but I just found out that he is not the biological father of this baby. I know who the father is and I have the paternity test to prove that he is not the father... he still wants to pursue the case. What are my chances of losing this child? He only supported the child for three months and that was it, also leaving him with an open case with DHS because of the baby's mother;s drug habbit.

Non bilogical father wants to take the baby away from me whom I have full custody of. He abandoned the child. What are the chances of losing this child?

Depends on the state and other issues

Is he listed on the birth certificate ?

If so, then in many states if it is not challenged within a period of years, he is considered the legal father no matter who the real bio father is.
There is not many states like this, but there is a few.

So basically in most states, you challenge it by DNA but you will need the real bio father to be signing over rights to you. Since proving he is the father then gives him all the rights.