What qualifies as proof of address for a child? He is not in school so I do not have any school records I could provide.

If your child didn't go to school, you can send in copies of medical records or a statement from a daycare provider for proof of address.

@brittneejune If this didn't answer your question, please clarify below.

He is not in daycare. I also do not know how to access medical records. Could I use a letter sent the the address with his name on it from Medi-Cal?

Yes, that would be a great start.  You can also ask use a statement you have received for him at the doctors office.