Legal Question in Real Estate Law in California

Let him sue. On what grounds does he have to not pay the rent, he was coerced? He signed the lease with you so unless there was fraud, coercion, or something the landlord did to the apartment that could release BOTH of you from performance on the lease, he has to pay. He is just being ignorant of the law. He is responsible for whatever was agreed to in the lease, if it is 1/3 of the total rent, then that's the amount.

Unless the lease has very unusual terms, the landlord can go after any and all tenants who signed the lease for any or all of the rent, at its option. The liability on a lease to multiple tenants is considered "joint and several."

Now, as between you and your co-tenants, your rights and responsibilities do not arise out of the lease, they arise out of the arrangements, understandings, agreements, etc, among you. If the deal was that X would pay 1/3 of the rent and Y would pay 2/3, X can sue Y if Y doesn't pay, and vice-versa.

Don't expect the landlord to give a hoot if X moves out, or Y is a deadbeat. The landlord will sue whomever is handy for the full load.

Note that my explanation is somewhat different from Mr. Doan's... I believe I am describing the usual situation. Your lease may contain different terms. I do agree, however, that your ex-roommate is unlikely to succeed in a lawsuit against the landlord, OR against you.