Unless the daughter is still living with her mother, the father might be able to get the court to terminate support on the grounds that the daughter is emancipated.
Yes they are still married
No, if they are married they have equal custody.
He killed his father and married his mother. (Unwittingly, but still)
No, once married he is emancipated.
No. If you're married, you're emancipated, and you're on your own.
He can still gain custody as the presumptive father.
The mother is 83 and still alive
When married you are emancipated so no.