State tax filing

It depends, if you and him meet the qualifications below then yes, you can. 

Credit for Dependent Parent in California

"Claim this credit only if all of the following apply:

• You were married/or an RDP at the end of 2022 and you used the married/RDP filing separately filing status.
• Your spouse/RDP was not a member of your household during the last six months of the year.
• You furnished over one-half the household expenses for your dependent mother’s or father’s home, whether or not she or he lived in your home."

This credit is worth at most $556. 

In order to claim your parent as a dependent on your federal return the following must apply:

1. They can't file a joint return unless they are filing to get a refund
2. They can't be claimed as a dependent by anyone else
3. They must have taxable income of less than $4,400.  This includes the taxable portion of his social security
4. You must have provided over half of their support for the year.  If his spouse is providing half of his support or they are providing half or more of their support for the year- you cannot claim him)
   • Support includes but is not limited to:
     • housing
     • clothing
     • medical
     • transportation
     • food

This means if they get food stamps and buy their own food, they are providing their own food.  If he is paying his Medicare Premiums from his Social Security, the premiums would be counted on his side.

You would need to contact Medical to see if you claiming him would affect his eligibility.