One does not have to be a lawyer to know the law. That's why I am asking what your attorney is basing his opinion on. I do have more than the average knowledge of Real Estate law from past experiences and I live on LI. It is certainly possible this guy knows something I don't. In which case I would like to know what it is. But to my knowledge it is unlikely you will win a case to recover any past rental.
We can only respond to what you tell us. You keep adding little tidbits of information with each post. If you had provided more info initially (like him riding around on a Rolls) our responses may have been different. Clearly this guy is going to get a reality check when the Town and County is informed about his violations. But just as clearly you will have to move and I doubt if you will see any compensation for having lived there.