It costs tens (or hundreds) of thousands of dollars to sue someone residing in another country... That's if you can even find a lawyer to take the case against someone in a third world country.

If you feel you owe him more, give him what you think he is worth to buy him out. If you think you owe him nothing, then cut off communication from him.

He has to sue you in your country of residence so until you start hearing from local courts, I wouldn't worry.