My dad has great insurance MVP Gold, but only in network in NY. He is moving to Georgia to live with us. What do we do?

Try AARP

My MIL has the same set up with her insurance. As long as she remains in NY she is covered, but this was a major deterrent in moving her anywhere else as while she would still be covered, her co-pays for everything would be higher as she would be considered out of network.
To be sure, I would call his insurance provider to ask. 

You will have to find another plan in Georgia. You can check the marketplace or see if your area agency on aging has info. Some states have better programs.