CalMed, SSI, ETC. Confused. Any guidance?

1099 is for independent contractors, considered self employed. If he paid payroll taxes on that income, he might qualify for Social Security based on disability. That can take a long time to approve. He should apply at the nearest Social Security office. While he's waiting for that, he can apply for California State disability at the Employment office. With both those, he will still be able to get SNAP, Supplimental Nutritional Aid, aka "food stamps."

However, if he did not pay into social security and state payroll taxes, he can only receive SSI. That is a disability payment through the Social Security administration. The state of California adds a small amount of money to the SSI payment in lieu of SNAP, so he would no longer receive separate food stamps. But SSI includes no-cost MediCal, the California version of Medicaid.

I suggest starting at the Social Security office. They should be able to tell him which program he should apply for. In order for you to assist in the application process, he will need to sign a form allowing you to act on his behalf during the application process.

He should file for SSI as soon as he can validate the pay through 1099.

From what I read a 1099 employee is an independent contractor. Meaning he is responsible for filing his own contribution to Social Security. He needs to go back to the division who provides his food stamps. He should be able to sign up for SSI and once done he maybe able to get Medicaid.

The local Health and Human Services office would be able to explain and help him apply for any benefits, although if he's already getting food stamps, he must already be in touch with them. The California Department of Rehabilitation helps disabled people return to work in whatever way they are able. From what I know of Medicaid, he must have very few assets to be eligible for medical help, but the HHS office would have this information.  Also, the federal Social Security website has a screening tool with which he can determine his eligibility; per the website, SSI is not based on Social Security taxes. I think the Department of Rehabilitation in California should have this information. Their website is very informative. I find the Internet invaluable to look up information on all the various programs; there are websites for everything, it seems! Good luck to him.

Unless he paid Self-Employment taxes on his earnings, he will not be eligible for Social Security disability. If he did pay SE taxes (as required by law), then he would be required to have a minimum number of paid-up calendar quarters to qualify for Social Security disability.
Don't know about CA, but look for a Dept of Workforce Development, Occupational Rehabilitation, or a similar agency.