My boyfriend is getting a divorce from his wife because she cheated on him while he was deployed to iraq and is now having a child that is not his my question is She has 3 children 2 of the children ared biologicaly his and the oldest one is not bio his but his name was added to the birth certificate when the child was 2 years old with out legally adopting the child does this make him finanically responsiable for the child if so can he fight for custody

If his name is on the birth certificate, for whatever reason, he is financially responsible and CAN fight for custody.