Telling him just before it happens, when he's paid school fees for a school she won't be attending certainly seems sneaking out to me. If they just found out and told him right away that'd be one thing but doesn't sound like it.
I'm saying he won't be blowing his money because it sounds from the circumstance like he can at least stop them in the short term and he can certainly then get orders in place to solidify his rights.
If they are doing this in a shady way, there's a good chance he won't end up paying anything - and regardless, if they're the ones want to move and are granted permission, it's very common that an order will be placed forcing them to pay for all transport costs for her and possibly him for visitation. I think that's a lot of help, personally.
I agree, at the very least make them pay to send her back and forth to see him. That could be a lot of money over 4 years.
I also don't buy the teens don't want to be around their parents. She is a very young high schooler, not 18 and off on her own. Kids that age spend a lot of time with family.
It was very nasty of the Mom to do it this way and he needs to get to court and get some things in place.