It's pretty much his thing. But, I'm not counting on it happening in TMNTU.
Mondo and Mike are just going to keep disrespecting his pain and putting their feelings ahead of Seymour's comfort.
(That and he'd be much easier to allow passage into Valhalla than say, Slash, who may also get some serious suicidal tenancies if he's saved)
I don't think that he'd join Leatherhead. More "Oh look, jaws of death!" Man, if we thought Krang was an easy snatch...