Full Custody does not mean she can move countries, now I am not familiar with the details of Indian laws on this matter but I would check first. She will soon I assume reach majority when this will not be an issue.
SB1 seems to have a very low success rate and I doubt that her reason, well your reason, I assume she had no say, would fly but not my call.
Prior to the current administration I would say get on a place asap, might still be the way, after all worstn that could happen is you file AoS. Well probably worse that could happen?