My mother doesn't work. She gets social security. Does this count as a job earnings

Social Security is not "earned" income.   If you are trying to determine if you can claim your mother as a dependent, the SS does not "count"---but any other income counts--like a pension, investment income, distributions from retirement accounts, money from working, etc. etc.

IRS interview to help determine who can be claimed:

https://www.irs.gov/help/ita/who-can-i-claim-as-a-dependent

Social Security is not earned income. It is a retirement benefit, not job earnings.