And that's before we even get to the fact that Jason's in a wheelchair, which is what the X-Men universe does when someone with telekinetic powers needs to seem more sympathetic.
OK, so Jason doesn't exactly pull off "sympathetic" so much as "Donnie Wahlberg's character in The Sixth Sense, as played by Crispin Glover." But you'd probably look a little washed out, too, if your Dad was using your brain to kill an entire race of people just because they remind him of you. Jason is a character who is built to be pitied, not hated. He's no more responsible for his actions than Master Chief is responsible for having worse aim when you're drunk.
As the climax closes in, Jason's dad is using his brain to trick Professor X into killing all the world's mutants. The X-Men figure out what's going on just in time, and Nightcrawler teleports to Professor X's side to find him sitting across from Jason in the belly of a crumbling dam.
"Thank goodness for the Protagonists With Disabilities Act, eh?"
Unfortunately for Jason, the dam is about to disintegrate and kill everyone in its general vicinity, he's in a wheelchair and he's spent the last hour helping his dad screw with the only people who could save him. Fortunately for Jason, there's a clear precedent for this sort of scenario that says you always take pity on the pathetic bad guy who's being taken advantage of. If you've seen The Goonies take pity on Sloth or The Karate Kid take mercy on Johnny Lawrence, you know that Nightcrawler's next move should be to lift Jason out of his wheelchair and tell him "It's not your fault" while a bear hug teleports them both to safety.