Just my opinion, but I think they did. He started attending the school (a private Christian school) when he was in 10th grade. He played basketball (and Sean T was the assistant coach) and was preparing to play football. The parts of the movie where Sean paid for his lunches was true, and their first financial interaction. Michael was couch surfing with a few of the families, including the Tuohys. In the spring of his junior year, they invited him to stay with them for senior year and he did. At that point, they started getting him ready for college.
Everyone really thought he was going to play for Nick Sabin at LSU, but Sabin left. Then everyone thought he’d go to Tenn, even to the point where his hs coach took a job there, but Michael decided on Ole Miss (closer to ‘home’, Collins was going there, and the Ole Miss coach also took one of Michael’s best friends as a player too). The Tuohys did all the tutoring, paid for the classes from BYU, got Miss Sue to do tutoring. The did the conservatorship just to appease the NCAA. Legally, I think the arrangement was stupid, but the NCAA needed something to save face and this worked. It was a ‘good ol’ boy’ arrangement. At that time, there was no book or movie deal, no charity set up, it was just them getting Oher into college.
One of the interesting parts of the Blind Side book was the other really good athletes from Memphis who didn’t make it into college, never mind the pros. They didn’t make it through hs, they fathered children and had to drop out, they got hurt, they got arrested. It also pointed out that those who did make it in college went to college ‘close to home’ like Oher did.
The Blind Side wasn’t written until Michael was in college, so over 18. The Tuohys didn’t abandon him in college, and in fact bailed him out (literally) when he got into a fight and a child was hurt (child was standing nearby).
I don’t know why things went so sour between Oher and the Tuohys. That seemed to happen about 4-5 years into his pro career, long after he’d established himself, after the book and movie were released. He had his own family by then (girlfriend, her 2 kids, and their child). He had his own lawyers and agents (football and books). He still lived in Memphis.
Many of his brothers had died. I think some of the timing of the Tuohy split (around 2012-14 I think) was that his bio family was really gone and he felt alone. I read Oher’s books and he just seemed sad and lonely, and like many pro football players he’d made some good money but had spent a lot of it too. Oher was highly paid, but not making Tom Brady or Peyton Manning money.