I don't know what you're confused on. You're the one who said "Sounds like he was not in the regular school, but in the school for troubled kids, for lack of a better term."
I just said I wouldn't leap to that conclusion as I know alternative schools are there for a variety of reasons not just singularly for troubled kids. You followed up with "It just depends. There are lots of different kids there for different reasons." which appeared to be in direct contradiction to your earlier comment that "Sounds like he was not in the regular school, but in the school for troubled kids, for lack of a better term."
Which is it? Alternative schools are there for troubled kids or alternative schools have lots of different students there for different reasons"