I don't have a good way of judging your son's baseball ability.
However, with the exception of perhaps considering applying to a "fallback" school, I think the schools that your son applied to are perfectly reasonable and he is likely to get in to one or more. Sure, Stanford is always a stretch, but with a 35 ACT (and GPA to match, and Mexican-American to boot) your son should be in decent shape at the others. From the NCED web site (https://nces.ed.gov/collegenavigator/)
- ACT Scores 25th percentile - 75 percentile
- Stanford 31 - 35
- Notre Dame: 32 - 34
- Cal: 30 - 34
- UCLA: 28 - 33
- UCSB: 26 - 31
It wouldn't surprise me if he got in to all five. As others have noted, though, at this point baseball at these schools would mean trying to walk on.