I don't want to speculate too much on what rides you would approve of for a concussion, but I do have a teen boy who can't handle movement rides for other reasons.
If you have Harry Potter fans, there's lots to enjoy in those areas without riding the rides. Three Broomsticks, ice cream, the joke shop and the candy shop, creepy details, and of course the interactive wands. My son also likes the theming in Jurassic Park, and walking through the play area, but I don't know if that would be safe or too tempting to play tag?
Poseidon's Fury is a walk-through attraction. My son also liked the Raptor Encounter just to laugh at how much I panicked. Also, the Fear Factor show and the Horror Make-up show might be appealing. I think that Terminator is closed.
Fast and the Furious feels pretty tame. Really, King Kong does too. But I don't remember if there are sudden stops. Maybe you could ride first and test them out?
My son likes the Seuss trolley, but we're big Seuss fans. I don't know if the One Fish, Two Fish would be tame enough, but getting sprayed is fun at any age. What about standing in splash zones or use the water guns to hit people on rides or in the Jurassic area?
Special treats like the Simpson's donuts might be fun. What about a Scavenger Hunt to find certain details (that you could find in photos online ahead of time), with each kid competing to find the things and take photos?