Besides doing like sit ups and push ups and some plyometrics anyone have any ideas?
I wish you a speedy recovery man. Did they say you will regain use of your hand in the future?
So you can do push-ups but I imagine that loads heavier than body weight would be too much of a load on that hand?
I think that something you may want to look in to would be the smith machine. Sit-ups and push-ups are fine but despite the problem with your hand, it should still be possible to work your legs. If anything training such a large muscle group like your legs should help to limit the amount of strength that you lose from being able to do most upper body exercises.
You could also try light-weight bench press in the smith (safety,) or on a flat bench if you have a spot. Again, I'm not 100% sure on your ability with that hand. But at least you would be able to get at that muscle fiber in your chest to keep it from shrinking too much while you recover.
One more thing, would a 'hook grip' (primarily using just your 4 fingers to grip the bar,) doing deadlifts aggravate your hand? If not, you could continue to do the big 3 lifts, albeit modified in some cases, and still maintain most of your strength and size while allowing your hand to recover.
If nothing else, I think you could at least do squats in a smith or leg press to maintain most of your strength via legs.