The best thing he can have, is a friend. No matter what diagnosis, it will still remain uncertain unless it's an official diagnosis. No matter what is going on, having a friend can be a great helpful thing to someone.
Some of it sounds like autism.. some of it also sounds like other things... I think this person may have more than one issue going on, that's causing difficulty in really pinpointing it.
having autism can actually be a positive thing, if his field of knowledge and curiousity is in the doctor career. People who find what they are good at, do exceptionally well in those areas. he maybe taking these courses, but for other reasons than just becoming a doctor. he might be really good with helping parents and others who struggle with the same/or similar things that he does.

the best thing that anyone can do for this individual right now would be to support him, and question what he likes and dislikes and who the person he is, is. instead of questioning whats wrong with him. and maybe in knowing those things, answers may start being noticed on what really is the issues at hand.
One thing that is extremely a "red flag" for me, is the part where you say he forgets to eat. that's not very common among people who don't have autism. and its hard for others to understand(in my expeirence). because normally the convo has went:
"why didn't you eat?"
"i forgot"
"how do you forget to eat?"
"i dont know... i just do."
"that doesn't make sense. you feel hungry, so you shouldn't ever forget to eat"
"...i dont know why, but i really do forget to eat."
"well that just dont make sense."
and the only explaination i have found for this is caused with having autism, nothing else explained it. nothing else even acknowledged it. other things came close, but it wasn't it. i get so focused in something sometimes (usually whats interesting to me, and i like), that i loose track of time, and also don't remember that i should eat, and i dont feel hungry until after i'm done, and have gone back to not being undivided attention to something, which then hunger usually sets in, and i'm sick from it.

do you know if he thinks in pictures, or in words? those on the autism spectrum have a lot of thinking in pictures kind of brain work. words come secondary usually. but also, as they say "if you've met one person with autism, you have met one person with autism". aka, signs, symptoms, and traits range from person to person.