How can a father who lives in Geogia gets visitation rights/custody if the child lives in Maine?

The father was there for the child but the mom threatens to take the child away if the father doesn’t leave and everybody got scared and came against him and asking him to leave. So he left but now he has a decent job and wants to be in the child's life again but the mother is so angry for some reason and doesn't want to even let the dad contact her. Would he be allowed to take the kid out of state? And if the mother is not financially stable, i.e. receiving help from the government, could he get full/primary custody?