I get a little concerned when I see posters focused on one school. Brown is a great school, but I think you need to broaden your search to "Brown-like" schools. This isn't just semantics, your son really needs to think this way. Brown is in the Ivy conference, and each of those schools are very different from each other. The one thing they have in common is their athletic conference and rules around how they recruit in that athletic conference. That is it. Brown is very, very different. So, my best advice would be to research schools like Brown and focus on who they recruit, where they recruit, and how they recruit. Years ago, Brown used to only recruit from private schools nationally, and they focused on hitting. In my Ivy experience (2011-2014) the top of their hitting lineup was pretty darn good. Defense and pitching were not their strengths. I don't know their recruiting strategy and focus areas these days. As for the other schools like Brown that is your homework.
FWIW - At the D1 level schools like Brown, and others want to know that others schools are seriously recruiting your son. He has to build a market for himself. Again, this is going to require that he broaden his search and consider many schools to build that market. Coaches need to know your son is in demand, and he needs to be given a reason to take him off the market (give him an offer).
PS...I will help qualify Absorber's comments about commits prior to 2021. Again, back in 2011-14 I saw almost all Ivy starting pitchers in the high 80s' with control of multiple pitches. There were a handful of guys in the low 90s. Relievers are a different matter entirely.
As always, JMO. Best of luck!