i have some speculation about what happens in the end.
either, he wakes up and it was all a dream. or it is established somehow he is definitely mad. those are the obvious endings. which is why i doubt either of them will happen.
one thing that the first series didn't touch on, is Sam's supposed background. we know he's supposed to be from Hyde. in episode 2, someone claims to recognise him from Hyde. how extensive is his backstory? he's met the 2006's Sam Tyler's parents, in 1973; what about the parents of the 1973 Sam Tyler? by my reckoning (assuming he is as old as John Simm is now) he should have been born in 1937.
so i'm thinking that he wakes up from his coma, all right. but he's in his 60s. and he's married to Annie Cartwright.
is this speculation based on any known facts? nope. but i had a wild idea and thought i'd put it here so if by some random chance i hit the right spot i can say "i told you so!"
how does this sound? plausible?