1. The tickets were paid for by a check from the GRANDFATHER, which does bug me that the mother wants the money since it was never hers in the first place.
3. Mangaed to sell sea world and the pirate dinner tickets for the exact price we paid and the airline just gave me a credit minus $90
5. I have decided though many of you are right this is so NOT my problem. I am doing everything I can in good faith to sell these tickets. So if they other Disney, Disney Quest, Universal and
MVMCP tickets do not sell then I will just hand them over and be done with it. I think the sooner the better, since it's been a month now since they broke up and my son says he shows no intrest in getting back with her. Shoot I even bought her a lanyard and some pins to give to her for pin trading for her birthday, which I am now stuck with.

I know not as much money huh?
(cool)
Ok...#1 negates everyone's arguments about her being a minor....your "contract" if there was one would be with the Grandfather....he's the one that paid you, he's really the only one that could make any legal argument for reimbursement. Has he said anything to you? I certainly wouldn't open a can of worms by contacting him first....BUT...if there is any money to be refunded because of the things you've been able to sell for them, it should go to HIM not to mom. And I'd do it in the form of a check with the note section showing exactly what it's for "sale proceeds from Disney admission tickets" or whatever.
Also, a word of caution.....I have a dear friend with a FIL who is quite wealthy.....FIL pays for many things, vacations, school clothes, extracurricular school stuff, etc. Love my friend dearly, but it disgusts me when she will do things to get cash from him.....like have him buy the kids the most expensive clothes at fancy boutiques/stores......and then return them and take the cash to
Walmart or Mervyns, pocketing the rest. Sounds to me like Mom might be a bit like my friend....hoping to get some cash out of this cancelled vacation. Everything else about my friend is wonderful, but her love of "free cash" as she calls it is stomach turning.
#3.....you aren't planning on taking the $90 loss right? Not sure what airline it was booked on, but most of them have a cancellation/change fee, and I've seen as high as $150 per ticket, so that loss is pretty much on par I'd say. If they give you any flack, be sure to point out the written policy that most of the airlines have on line.....and I'd throw in a jab at the fact that YOU are doing all the leg work for this so if they thought they could negotiate better perhaps they should have stepped up.
#5....if it's been a month then yeah, I'd stop the extra work. I'd give the tickets back to Grandfather......because again HE is the one you "contracted" with. If Mom balks, I'd flat out tell her that you're very disappointed in how this has been handled by her, and you're doing this to protect your family because of the threats she'd made. Grandfather paid you, you're returning HIS money to him. I'd also make a copy of the tickets that you are returning and ask him to sign for them. If he's a reasonable man he'll understand your trying to protect yourself....if he's not, then all the more reason to insist it be signed for. Not sure if these tickets have identifying numbers on them, but that's what I'd be aiming at copying. Sad to have to go to such lengths to protect yourself, but you'll be glad you did if Mom decides to try to pursue it legally. Of course, if Mom filed suit first thing to do is request a dismissal since Mom wasn't a party to the original transaction, Grandfather was. LOL...that'll piss her off though.
As for the lanyard and pins.....you can certainly use the pins for your family to get a few that they'd enjoy. If your family isn't into pins, then maybe consider donating the set to Give the Kids The World. It's not that huge of a financial loss for you, all things considered, but it could make some kids' trip extra special.....and that can only make you feel better about this whole thing.
I hope that things settle down and you and the girl are able to continue a friendship.....probably not for a while, but I wouldn't write her off completely. Maybe send her a birthday card anyway (non-Disney though, lol)....and keep in touch if only by Hallmark card moments for a while. Sounds like she's set to graduate next year or the year after so once she's out from under Mom she may be grateful for someone like you in her life.
Go forth knowing that you went above and beyond.