If your tenant is jailed, obviously he will not be using one of the units he rented from you. If he cannot keep rent current, you have every right to evict him. If he is behind in rent, you should serve him with a 3 day notice to pay or quit at the jail house. If he does not come current on the rent in this time period, serve him with an unlawful detainer action in order to end the lease.Given the unusual circumstances of your tenant, it is probably a good idea to retain a landlord tenant attorney to assist you in the process to evict the jailed tenant so that it is done correctly. You can cash the partial rental payment from the tenant's mother to cover part of his owed rent.Good luck.