No problem! What he can do is apply to the normal undergraduate places he would normally go to if BA/MD and BS/MD programs didn’t factor into the equation, and then apply to some of the combined programs he wouldn’t mind going to if he got an acceptance, based on the medical school. If he’s interested in programs like Brown, Northwestern, Case Western, etc. then for some of them he may need to take the SAT subject exams that they specify in order to apply. His standardized SAT/ACT score will probably have to be pretty good as well, so he should try and prepare as best as he can.
Neurology as a residency isn’t competitive, although the very top programs in Neurology, will, of course, be competitive, but even those aren’t assured coming from the schools you mentioned. This is assuming of course, that he sticks with Neurology, when things will likely change, and of course there are related fields like: Neurosurgery, Radiology (w/Neurorads fellowship after), etc.