Furthermore, even if enough time elapses between concussions to allow the brain to heal, repeated concussions can result in nerve, learning and memory problems.
Q : I believe the function of "to allow the brain to heal" could be two possibilities. One is it modifies "time" as an adjective. The other case is it modifies "elapses" as an adverb, showing a result of it.
what do you think?
All the best,