A couple things to add as I think TwoBoys did a great job covering the question.
Pre-reads for any HA school is incredibly important for you and the Coach. The Coach typically knows what metrics he needs to recruit a player, but getting added validation from Admission is key before verbally offering or issuing a LL to Ivys. Remember, Admissions holds the keys to the HA kingdom and can trump a coaches recommendation. If they've already pre-approved a recruit then the Coach knows he won't have to battle to get that recruit in, and he can focus on other recruits. Always look at these situations and processes through the coaches eyes, and understand where you fit academically and athletically in his recruiting pool. He only has so much equity with Admissions. If your son is on the plus side for academics and academics then your in a good spot. If your son is on the plus side athletically and on the negative side academically then it gets dicey.
I've not met anybody targeting HA schools on this site that has not had a pre-read. This is the recruits opportunity to find out if there are academic objections and enough time to remediate those objections. I Which gets me to my next point about when do they ask to do pre-reads. Most Ivys/Patriot schools are going to be months ahead (of D3s) in their pre-read requests as they are competing against D1 scholarship candidates with NLIs or verbal offers. Most of the D3 HA schools are going to be late Summer/early Fall.
Also, I'd pick a couple schools that have offered to do a pre-read..schools that he is somewhat interested in. Certainly there were schools that my son was not interested, but he kept that to himself. Honestly, there were schools that really surprised us (both ways). Go through the process to better understand it, and get a sense of his value in the marketplace. Weigh your options as they come in. This is exactly what the coaches are doing.
Good luck!