Child custody in different states

Megan

Ok idk if this is the right group but I have a major question. My stepson (2 years old), his mom married a marine and promised us if she moved (we have 50/50 custody) if we let her move she would move back in a year or 2 because he was supposed to be getting out. Come to find out, he re-enlisted into the military and they are now moving to SC (we are in TN). The child will be in school in 3 years. His doctors are here. His siblings are here. His family is here. Since she has moved she neglected to keep him up to date on his shots, and has neglected to take him to any of his doctors appointments. Does anybody have any experience in these custody cases??? I’m so worried my husband is gonna lose 50/50 if we go back to court