If father likes to claim guardianship of minor children, he has to approach the Guardian Judge and apply for guardianship/custody of minor along with providing proofs of second marriage of ex-wife. The Guardianship/Custody petition will be decided in accordance with law and with the due process of law.
The point is that the second marriage of wife is only a ground for dis-entitlement of wife from retaining physical custody of minor children. The husband still has to contest and has to prove to the court of law that the welfare or minor rests with him and minor is willing to live happily with him and not with the mother.
For more queries you can always drop an email at firstname.lastname@example.org
Salman Yousaf Khan (Golra)
International Family Attorney