I hope he can make it back into F1. Unfortunately if you look at the video where he is spraying the champagne his right hand has no strength. He is just holding the bottle to keep it steady and there is little motion. He quickly pulls it away and uses his left hand for all else including the hand shake.
The reports I hear are that he drove the car mostly with one hand. His injured hand was just there to hold the wheel steady. He must have been able to use it for the hand brake though. You can see he has paddle shifters on the left side of the steering wheel in one of the vids, can't see the right side.