Hi there. I'm the mom of an addict who also spiraled downhill quickly during these same years. I understand your feeling of desperation. Been there.
We, too, just hoped he would 'snap out of it' and kept giving him another chance, another semester, another school, etc. We're out $30,000 and he has 2 YEARS of failing grades to show for it. We also sent him to rehab (another $10K) and he relapsed within a week of being home. (Allowing him to come home was another mistake.)
If I had the chance to do it all over again I would pull him out of school after that first failed semester and set up rules and boundaries at home for him to continue living there while he got a job and would be allowed to take 6 hours at school. If he broke the rules or failed the courses, he would have 30 days to find other living arrangements. And, here's the hard part... I would have never backed down or wavered in any way about these conditions and boundaries. I would not have bailed him out when he got arrested nor would I have hired an attorney (Another $7,500).
Just sayin.....