Have you asked your brother if he will accept or even if he wants help? He’s 25 its hard enough taking help when you’re much older let alone when you’re a young man, I know you mean well but never under estimate pride.

As for timings double everything, there won’t be any whizzing thru at last minute anywhere. You can pick up a wheelchair and self push him at assistance desk. Otherwise I would say option 2 is best bet as he won’t be able to do stairs/steps if there’s no air bridge.

Don’t under estimate how much longer everything takes when you are mobility challenged.