My D narrowed it down to 2 and then waited until a couple days before decision day to make a decision. Her choices were very different from one another and would offer her very different experiences. I think she had a strong favorite (which she ultimately chose) but was concerned about the distance from home and travel. We tried to stay out of the decision as much as possible. We talked about it a lot and discussed the pros and cons of each but 100% wanted it to be her decision.
I agree that going to admitted student’s days is a great idea. It’s more time on campus and with other students and faculty. It sounds like your son has good options, so he can’t really go wrong. I mean, if he goes with the school that is showing him the most love, then fine. He’ll feel wanted and happy about his choice. My daughter is currently applying to grad schools and one school is really doing an amazing job with communication, reaching out, providing information, etc. Since she’s the type who likes a friendly, collaborative environment, it’s hard for that not to influence her a bit.
Congrats on the 3 acceptances!