Marist does offer excellent supports BUT: 1) it is a mid-sized university, not a LAC; 2) the school has a bit of a Catholic vibe if that is an issue; 3) there is a big commitment required on the part of the student (meetings multiple times a week); 4) there is a cost to this program (looks like $3,000/semester from a quick search). Hofstra and Adelphi are both to some extent commuter/suitcase schools and again, they are not LACs.
To the OP: Have you met with someone in the Office of Disability Services at each college? I think many schools have similar offerings.
The truth is much will depend on your son – I imagine you already know that he will need to be more proactive in college as compared to HS. For accommodations (ex. extra time on exams) the general protocol is that the Office of Disability Services will give your son a letter and he will need to make arrangements with each professor. For extra help, he will have to seek out professors during office hours, the writing center, etc.