My first step would be to contact the small LAC he was planning to attend and talk to them. As a senior with only a semester left in school, there are many variables. First, he may have enough credits to be admitted. Second, he may be able to take the GED. And, while it may not be easy as suggested above, I would think a student who has been attending a private school and is one semester from graduation could manage to pass. Third, he might be able to transfer to the local brick-and-mortar school, but I would check to see if there are any requirements that he attend for two semesters before graduating. Finally, he might be able to home school/virtual school, but I know in my state that parents have to submit a declaration of homeschool and a syllabus, and there might not be time for that. Also, some colleges have testing requirements for homeschoolers that he likely hasn’t taken. Also, definitely have him study independently for the AP tests and take the exams if he does not transfer to a brick-and-mortar school.
My second step would be to go ahead and apply to both your state university and a local community college. They generally have longer deadlines (our state flagship accepts applications for fall until some time during the summer). Same scenarios could apply.
While being caught with a vape may not, in itself, concern the college(s) much, the fact that your son broke his school’s honor code might. But, the implications for a state university would be less severe than a private one.