Does a mother who abandoned her 4 year old daughter has any right to take her?

the wife of my nephew abandoned her 4 year old daughter and husband right after she graduated from college (she graduated march 2012 & left them after). I did send the two of them back to school 3 years ago so they could finish their studies and be able to give good life to their child (my nephew is now on his last semester to graduate). Now, the mother is claiming rights to her daughter. Well, we heard that the girl is living with another man. BTW, they are married in church (my nephew and his wife). Does she have any right to get custody of the child? what are the legalities i need to know? of course we don't want the child to grow up with her knowing that she's living with another man.. please advise? thanks

if the child is at least 7 years old, let her husband resist it

Unfortunately, as of now the child is only 4 yrs old. Does this mean that the mother can get the custody? What can the husband do for the child to stay with him?

a bit tricky situation. the law clearly states that custody should be with the mother, and by refusing, he can be charged with ra 9262.

if he will resist, i recommend he files a case for custody to justify his refusal and he can prove why the wife should not be given custody