The first thing I would recommend is talking to your son's school counselor to come up with a plan. Ask the counselor to call various schools of interest to see if they would take a late application from your son. You need a school counselor to do this - an independent counselor can call and put together a list, but the school counselor likely knows which colleges have the strongest working relationship with your particular high school. Even if you felt the school counselor wasn't the best at giving advice, you need their help. Insist on it.
There are actually quite a few colleges and universities which are still accepting applications. For instance, Drew University in New Jersey is still actively soliciting applications, but there are many more who are as well (I have a list of about 10 schools in California alone) After May 1, the National Association for College Admissions Counseling also will post a list of colleges that still have spots in their freshman classes they're actively trying to fill. You can find the list at
NACAC - Home page Last year, there were 220+ colleges on that list alone.