Those aren't the results of a failure, even if they had been achieved without the backdrop. The fact that they were achieved despite his school letting him down makes them all the more impressive.
I'm really sorry, Ggirl. If DS had gone through that and was feeling like that, then I'd be desperate to help him. At the end of the day, he's your son, and it's terrible to see your child suffer. I really feel for both of you. I'm sure you've told him that he's let no one down, not himself, nor your family.
If he struggles with exams, and doesn't do himself justice in them, then maybe he's going to be more successful in the long run with BTECs?
I know the college isn't what he wanted but I sincerely hope he'll be happy there.