This is complex enough that Dads only option is skilled counsel.
Not clear if they are divorced and/or what any custody order says and waht state has jurisdiction as to divorce if any.
Generally a product of a marriage is considered to just that, even if Dad is not Dad by DNA--and in a way Dad may need to quickly contest/sort it out as he could otherwsie be on hook to pay for kid not his own--thru college!
Ordinarily Dads right would trump anything GP's have to say--but given GPs now have some sort of court order Dad risks winding up in jail if he tries to spirit his own kid a away
By waiting so long--the jurisdiction as to child is now very likley VA not PA and it gets worse as to visitations etc. Unless PA was original jurisdiction?
Dad needs very good counsel in VA--nothing less is going to help!. If Dad failed to use counsel in round one, which I bet he failed fo use, he dug himself some major holes . It makes little sense that Dad could not promptly recover own child --but he took a rubber knife to a gun fight--with predictable odds .