How much the school wants him (unless it is demonstrated by a big increase in their merit offer) is meaningless, has absolutely nothing to do with what his experience will be once he’s there. Accepted student days don’t mean much, either. They have nothing to do with his future experience there, other than that he’ll meet some future classmates.
The best thing that he could do at this point is visit the schools for a few days, staying in the dorms with someone, eating in the dining halls if he can be smuggled in, and sitting in on some classes he intends to take. Do you or he know anyone currently attending these schools whom he could arrange to visit for, say, a Thursday through Sunday visit? That way he could go to two days of classes, and see some of the weekend social life, too. If you belong to any religious organization, that can be a way to find someone to stay with. If he is involved in any wildlife conservation group that has a branch on campus, that could also be a way to find someone to connect with whose currently a student there.