Thank you for the additional information,
Your son's fiancé will need to file a Motion in the SC family law court where the other orders were issued and seek permission to relocate to another state with her child.
The court will determine whether the move is in the best interests of her child. And I have to say that if she is married by the time she goes to court---this will make it much more likely that she will be granted the right to take her child out of state---to go with her new husband.
Some of the issues the court looks at when a parent seeks permission to relocate out of state with their children are as follows:
1. Whether the move would result in a better quality of life the children
2. The extent to which the remaining parent exercises visitation rights with the children.
3. Whether that parent is willing to allow their children to spend longer, though less frequent, visits with the other parent, if the court approves the relocation.
4. Whether the child will be in close proximity to extended family members at the new location.
5. The quality of education and the quality of life the child would have access to at the new location.
6. That the relocating parent is prepared to pay for the increased expenses associated with the children’s traveling to and from visits with the other parent.
7. And, that the relocation is not simply an attempt to limit the other parent’s time with the children as some sort of punishment or attempt to be controlling.
8. Always, the primary consideration for the court is whether the move would be in the best interests of the children.
When the judge grants the move, she will also have to have a new child visitation schedule ordered by the court---which will result in less frequent visits by the father, but longer visits.
You may reply back to me again, using the Reply to Expert link, if you have additional questions.
I wish you the best in your future,