While most high schools programs are currently preparing for Spring football, college programs are busy organizing and promoting their summer camps. I don't believe that summer camps are the keys to eventual college draft that some would claim them to be.
First and foremost, college camps are designed for one primary purpose: to supplement the income of college coaches. Sure, they will be promoted as helping develop your son's skills, but if the drills they are running are in conflict with what his own high school coach runs then there is very little value.
If your son is an underclassman, the only real value to attending that camp for him is to perhaps experience 'college life'; being away from home for a few nights, sleeping in a dorm room, eating in a dining hall. Based on my own observations and feedback from other parents and student-athletes, underclassmen are generally after-thoughts at most college summer camps.
If, however, your son is between his junior and senior year, he has the potential to be noticed at the camp by the school's coaching staff. The key here is to not waste time and money by having him attend the entire camp.
Most schools will hold a Junior Day (or it may be called Senior Day) at the start of their camp. This is a day for student-athletes and their parents to attend a presentation by the coaching staff, tour the campus and facilities, visit with current players, and have lunch. The schools are required to charge a nominal fee for this and it is well-worth it. I would strongly recommend attending this event.
I would also recommend just attending the first day of camp subsequent to the Junior Day. Make sure your son's position coach knows that he will be there for only one day so that he can be observed and evaluated.
If the school does not host a Junior Day event, then reach out to your son's position coach or camp director before registering, and ask which would be the best day for him to attend to be evaluated.
I saw with my son and several of his teammates that summer camps can cause burnout; after attending two full camps, my son had had enough and no-showed for a third, which had already been paid. So plan accordingly, don't overwork your son, and by all means, enjoy the camaraderie that will develop among parents in the bleachers.