URGENT! Child has been moved out of state

I have a few questions…
The 6 yo child has not been allowed by the mother to see the father (very sporadic visits = 3-4 times within the last 5 years)
Father pays child support.
Father has been contacted by one of the mother’s relatives who has the child & one week prior the relative informed the father they were moving to Atlanta. The father has been in daily/weekly contact via phone with child since.
Father wants custody.

Does the father have the right to go get the child from this relative LEGALLY?
The parents are married but have been separated for 4 years & no custody has been awarded by the courts.
The father is filing for divorce but the main concern is the child’s welfare & being able to interact with the child without the constant fear that the mother will resurface & disappear with the child again.
What legal rights do the father have?
Should he file for emergency custody?
What immediate actions/steps should this father take?

The mother’s whereabouts are unknown at this time but is suspect that she is in yet another state besides NC & GA.

Please advise.

No, even if no custody order is currently in place the mother could file an emergency action in the event the child was taken. The father must file an action for child custody and proceed through the courts. I suggest the father meet with an attorney to discuss the details of the case (and determine whether an emergency action is appropriate) in the near future.