Can the land lord kick out the tenet?

My roommate who lives with my in the same apartment is not able to pay his last month rent. He already gave notice of leaving to the land lord more than a month ago and he already paid one month of rent as a security deposit to the land lord. We pay cash for our rent and we didn’t sign any contract, but we have receipt of paying security deposit and our rents in each month. Now my question is, can the landlord kick him out in this last month bcs he doesn’t have the rent to pay. Btw we live in Northern California.