Just so you are given fair warning, this is the big disaster that really sparks the main conflict of my story.

So, it's not a huge spoiler, but it is one.
My protagonist James, is a 21 year old orchestral violinist. He is fairly active both from practicing (It
is physical activity!) and helping his grandparents maintain their land during the summers. Here is my medical timeline so far:
1. Someone does something to spark all of this. I'm not sure yet if a blood thinner or a blood pressure med like Midodrene would be best, or if there is another root cause I could explore. Basically he gets knocked out, and something is administered that said bad guy thinks will make it look like he died from an existing medical condition - that he had a brain aneurysm or stroke or something, then fell, hence the head injury.
My protagonist is found and brought to the hospital, treated for concussion, no further problems found because said bad guy works in the hospital and switches out James' blood with his own before the blood test is run.
Information curtesy of my sister who works in blood bank - it would be easy to do.Goal: find something he could administer that would have a delayed enough effect he would be released as fine, but to be watched as you would with a standard concussion. It is only known that he was knocked out.
2. At some point the next day (?) he notices a bit of right hand weakness (I will likely express this with him having difficulty bowing some passages while he practices.), but nothing else. His friends see that something is wrong, he just doesn't seem present, and convince him to go to the ER. An MRI shows he is having a stroke, but there aren't any severe symptoms. The next morning-ish the ER doctor releases him because he is walking and talking and seems fine.
Starting with point 2, I'm actually using a real event I heard from the person it happened to.Goal: Portray the order of tests, etc. accurately. They can't find the root of the problem yet for my plot, so if the root cause would have shown up I may end up needing to combine this somehow with point 1. Said bad guy is in jail at this point, so he won't be able to do anything else to instigate things.
3. For three days there isn't any change in how he is feeling, then at the end of a concert there is a sudden rush of symptoms : Sudden, intense headache; inability to comprehend his sheet music; nausea/vomiting
I may take that out because it's gross... or just try to mention it in a non-gross way... 
; sudden severe weakness down right side, slurred speech. In the scene, they sort of snowball, so it's not like one moment he's fine and the next he's completely debilitated. EMTs come, he's taken to hospital unconscious.
The person I talked to woke up about three days later with a completely dead, although not numb, arm and some other symptoms. So this is more dramatic, but I'm using the same timing between incidents.They do whatever they would do, it is found that he has had another or worsening of the same stroke.
She said the hospital told her the stroke had been going on the whole time... not sure how they could know that. Since they would re-run bloodwork they would find the root cause and deal with it.
Goal: Portray accurately (probably from James' perspective, so there will be some holes) what would happen, how long he would be unconscious/in the hospital. When would they start therapy, etc.
4. He is left with near-paralysis of his right side, the ability to comprehend speech but not speak himself due to lack of muscle control (Apraxia), the "ability" to communicate through attempting to write with his left hand, and of course a whole lot of distress over his condition. He will recover to the point where he has a charmingly lopsided grin, can walk (Maybe with a tendency to limp or use an awkward gate?), can write/use his right hand (although a bit clumsily.). As to the violin, I may allow him to play but to portray his right hand like that of a child just learning to play, where his left is still that of a proffesional.
There you have the big picture!