Sue roommate for his share of rent?

[DavidHeisel]

While going to college in NY state, me and 2 other guys agreed to share a house together because we were all moving to Charlotte, NC for grad school. We all signed the lease. The 3rd roommate signed and paid security deposit, but an hour before we drove to Charlotte he had a nervous breakdown and moved back to his parents house in Boston, Mass. Now we are stuck paying his share of the rent and cannot afford it on our very low paying grad school assistantships. We don't want to lose the house and are looking for a new roommate, but want to sue him for his share of the rent until we can find a replacement.

Any idea how this can be done? I heard small claims wolnt work because he never moved down here to Charlotte. Would we need to sue him in Mass small claims, or what?