Been a while since I seen the movie but from what I remember the the guy didnt have a pot to piss in or a window to throw it out of. Poor student, pretty much homless and no real direction or role models. In and out of foster care. No real role models. Thats just what I can remember from the movie. How true the movie is I dont know.
From what i've been reading, Oher was already attending Briarcrest and getting noticed for his sports ability before starting to live with the Tuohy's. He wasn't in a stable home situation, though.
I don't doubt that the Tuohy's did a lot to help. But i don't know how much they really 'saved' him either.
Either way, you'd think that someone who was struggling to find a place in the world and a home life would be the last person you'd want to lie to about adoption. Especially if a lot of money then becomes involved.