You said to keep it short and just fire the right hand, but if he throws a 1-2 or a jab right hook you could get caught so I like to parry the jab then jab his right shoulder to stop the rear hand then fire the 2
In boxing we're taught not to parry with the lead hand because someone can feint the punch then loop it to throw a hook. A safer alternative would be to just parry with the rear hand then fire your lead punch back after bringing your rear hand back to your face.