Can i claim my adult son who does not work and I provide all support except he has medicaid and has an ebt card for food(340.00 per month)?

Sounds like you can.

---Tests to be a Qualifying Relative (& Unrelated Persons)---
(Must meet ALL of these tests to be a dependent)

1. The person cannot be your qualifying child or the qualifying child of any other taxpayer.

2. The person either must be related to you, or must live with you all year (all 365 days as a member of your household - There are exceptions for temporary absences such as school, illness, business, vacation, military service).

3. The person's gross income for the year must be less than $4,300 (tax-exempt income, such as certain social security benefits, is not included in gross income)

4. You must provide more than half of the person's total support** for the year.

5. The person is not filing a joint return.

In any case, the person must be a U.S. citizen, U.S. resident alien, U.S. national, or a resident of Canada or Mexico

The above is simplified; see IRS Publication 501 for full information.
https://www.irs.gov/pub/irs-pdf/p501.pdf

** Pub 501 Worksheet 2 for determining support
https://www.irs.gov/publications/p501#en_US_2020_publink1000292527

If he lives with you all year and you provide over half of his total support, you can claim him as a qualifying relative.   To claim an adult-dependent:  

• They don't have to be related to you (despite the name).
• They aren't claimed as a dependent by someone else.
• They're a U.S. citizen, resident alien, national, or a Canadian or Mexican resident.
• They aren’t filing a joint return with their spouse.
• They lived with you the entire year (exceptions apply).
• They made less than $4,300 in 2021.  (medicaid and ebt do not count)
• You provided more than half of their financial support.