landlord and old roommate issues!

Location: Massachusetts So I had a roommate move out in the middle of the night on a joint severalty lease in saying he’s not paying rent anymore. His dad is a lawyer and in order to fight him my landlord had to spent hundreds on his own lawyer. My landlord gave up and said whatever he can move out without paying. However now I’m paying thousands extra in rent. I don’t think this is fair to me but I don’t even think I can take my old roommate to court anymore after what my landlord told him. Please help what do I do