Some (maybe all?) of the UC’s have specific pages on their web sites addressing LGBTQ housing issues – some have specific theme-based housing included among options.
UC Berkeley: http://ejce.berkeley.edu/geneq/resources/lgbtq-resources/housing
UC Davis: http://lgbtqia.ucdavis.edu/support/housing.html
UC Riverside: http://out.ucr.edu/ourcampus/housing.html
Those are just the first 3 results that came up for me in Google with a search for “lgbtq housing uc”
If your son is headed for another campus, you can just add the campus name to the search I did and I’d expect that you will quickly find the appropriate resource.