Afaik, and you can't use crowd sourced info like this as some kind of realistic guide, it should be handled by his case worker. I'm not very familiar with cali state stuff, only what I've picked up talking to online support groups. But, iirc, he should get something in the mail every year telling him what, if anything, he needs to do.
My yearly letter is just a "you all set" kind of thing, but I'm east coast, so it isn't a guarantee of anything for his state.
Best bet is to contact his case worker and ask. If he doesn't know who that is, contact the local dss office and they'll be able to help to some degree or another.