I'm a drummer. I broke my hand a couple of years ago when I crashed out of a motorcycle race. They told me I'd be in a cast for a month. I had 'em cut it off after 2 1/2 weeks. In the meantime, I figured out how to hold a stick with a cast covering my palm and last 2 fingers and kept practicing with my band in the meantime.
Another time, I fell off my dirt bike riding in the woods and broke my elbow. Had it in a sling for 3+ weeks and could not use that arm to play drums at all during that time. Then when I could, the pain was the worst I've ever had (and I have had a LOT worse injuries).
How long it takes your guy to get back to somewhat normal playing really depends on how bad the break is. But, I've seen a number of one-armed drummers (and been one) that did just fine. Your guy should continue to practice with you like that in the meantime. He won't sound as good as he will when he's healed, but he can still be learning the songs - basic grooves, where the breaks are, etc.. Since he's new, I assume he's got a lot to learn about your set list, and he can make a lot of progress even with a broken elbow.
Speaking of broken elbows, they are nasty because of the range of motion that you lose while they are healing. It's a lot worse than most other joints. So, expect him to be able to start playing again in 4 - 6 weeks. But don't expect him to be playing WELL for another month or 2 after that.
Thanks! This was very helpful. Just what I was needing to know.
