I moved to California from East in 2002 and also lived Santa Monica for a few years. I lived a walk from the beach near Montana and Mark Jackson lived in townhome next door(nice guy!). It was awesome and for someone in their 20’s or early 30’s , amazing place to be- especially with money. Traffic not a factor in many places you could live and many places are private. If he wants the ocean and views that take your breath away, it will work. Personally, I would have never left California after a decade there but I was forced into leaving to somewhere just as beautiful but in a different way. The ocean still calls me back though.
San Antonio is super hot and humid- Santa Monica area/Malibu is in a whole other world. If he enjoys colder winters, and another country, Toronto will work but for someone who craves hotter year round weather, the choices get very narrow.