He always has acted like a baby to some extent but now it's getting out of control. He is fluffy, bobbing his head slightly as a chick, and does wing flicks (baby conure thing) if I put my fingers next to his beak, he will think it's feeding time and bob his head rapidly. Do I need to feed him baby formula or ignore it? He eats himself but still wants me to feed him. Should I give in?

Hm, I heard about this before. Handfed birds go into a sort of "relapse", so to say. I've never had it happen, and hoping it won't happen with Alex.

I wonder if this is a result of the incident.
Is he still eating solid food, or is he refusing it altogether?

I'd say feed him that way if that's what he wants. If you don't have actual handfeeding formula you can give him warm oatmeal or something like that. Or grind up some pellets in the blender and mix them with warm water. He's recovering from a nasty accident and needs all the support he can get.