I’m confused. It sounds like he attends a rigorous HS - difficult to get top grades, a large variety of AP courses (three years of AP Physics, AP Latin, etc). Has he received any guidance from his HS counselor?
Look at this grid to see which majors are impacted at the different CSUs. I would look at campuses other than Fullerton, Long Beach, Los Angeles, San Diego, San Jose and San Luis Obispo.
When you talk about visiting, would you like to be within a couple hour drive or are you okay with him moving an hour flight away?