I honestly hope that he would consider trying to enroll in a university. In his area, this is the smart way to deal with a situation of being young and homeless. It makes the transition out of one's parents' custody a lot easier.
The last day of the year to submit a FAFSA form is June 30 if he wants to try to enroll in a college and get aid. I think the state of California might actually have generous grants for college students, and if that is the case, then he might be able to enroll in an engineering or IT program at a local university. If he can get a degree from any institution in the Bay Area, even a technical college, he's probably employable in most parts of the world after that.
Again, you have to escape that "dependent student" designation. It exists because there are actually tax deductions for dependents that are worth about the same as the grants you can get in most states, so it's not that the government doesn't want to help just because you are young. They just assume that the best way to help you is to give your mom and dad a tax-deduction if they need it. The only way they know that your mom and dad have really genuinely fucked up is if you get documentation anytime you have to stay in a homeless shelter for any length of time, and it is clear that you cannot even rely on them for a place to wash your clothes. You go to the financial aid office at any college, and you keep hanging out there until they let you talk to an administrator that can help line you up with a dependent status exemption. Once they have realized how perilous your situation is, they will walk you through it. They only know you are telling the truth and not just high if you have documentation stating that you have been having to stay at shelters.
I am going to say that California tends to have superior higher education grants to most other states, and after textbooks and classes, he would probably be able to earn enough working weekends to pay for a single room. If he were living in Bumfuck County, Mississippi, then I would have to tell him he was looking at having to apply for subsidized loans, which are a pain in the donkey to pay off, but we are not talking about Bumfuck County, Mississippi. We are talking about the Bay Area, California, and they actually fund their education system, there. A good degree from a college, tech school, or university there would be more than adequate to get him into a comfortable apartment and a used Tesla.
As with everything else he ever tries to do, his health and possibly his life depend on him hanging onto everything he gets anywhere that is printed on paper, or if it is stored digitally in the cloud, he needs to know where in the cloud to find it. He needs to know that he must never lose track of any documents. If he does not feel confident about his ability to keep them safe while on the street, then he must find a friend or relative that can hang onto those documents for him. It's no big deal if he is naked: he is in the Bay Area, man. People go naked there for fun. If he wants to, he can spend the entire summer living naked in the trees and eating fruit like a primitive animal. People have done that, while tripping acid. Not having access to important documents is literally worse than being bare ass naked. This is the most important lesson that a young person should ever learn. He must know to hang onto them, and keep them safe. It can take you several weeks and no end of running around from one place to another to get them replaced, and you can't really do much of anything until you have them.
I honestly and truly hope that getting enrolled in a college fast is an option for him. If he can get enrolled in a college, then he can sleep in a public park and pretend he's in summer camp or something while waiting for move-in day at the dorm. If he can get that dependent student status exemption, then there is a lot of money in grants waiting for him, and that plus a weekend job can actually pay for a very good quality of life. He just has to get documentation anytime he stays in a homeless shelter or has any other interactions with society that are related to him being homeless, such as getting arrested for vagrancy for falling asleep in the wrong place.
On documents, here's one thing: sometimes, police do arrest people for petty and stupid reasons if you are homeless, but if they do, they are really helping you if you are college age. Judges almost always throw those cases out, and that just leaves the police report that acts as evidence that someone is not actually able to get adequate shelter. It's one more document that you could take to financial aid to get around that dependent status. The thing to do is find out how to get access to the police report, and ask for printouts.
All documents, including receipts, are important. Sometimes, a financial aid administrator is in hot water for allowing too many exemptions that turned out to be phony, but if someone comes with a pile of papers that include police reports, printouts from homeless shelters, receipts from food banks and thrift stores, and any other evidence you can bring that shows you are seriously, not kidding around, not able to rely on your parents for jack shit if your life depended on it, it gives the financial aid administrator a shield to say, "this one was real." That person can get in serious trouble for letting too many phony exemptions get claimed. You have to do anything you can to help protect that person. This is really true for getting anything done. Financial aid exemptions are only one example. Everything you do in your entire life goes easier if you keep documents handy.
