We had one like this a while back. Always complaining even though we fixed maintenence issues same day and did upgrades for them. Rudeness and ridiculousness actually increased the more we bent over backwards to please them. Then there were always the late rent excuses, we dont think we should have to pay the late fee, I don't have money for kids food followed immediately by their facebook pics of beach vacation, accusing my wife of putting their rent money order (dated and time stamped of course) back in their apt to illegally charge late fee, claiming we weren't allowed to enter their unit even after proper notice or when they requested repairs and telling us they had us on camera
We served 30 day notice for them to leave after they went month to month. They of course angrily threatened to sue us. Tenants like this are the absolute worst part of this business.
Nicely and professionally tell this guy you'll see him in court and formulate a plan to get rid of him. Or maybe throw some money at him to get rid of him if you want. Whatever you decide, I would advise taking back control from this idiot. It will only get worse if you cave - doesn't matter if you or tenant are in the wrong.