5 years ago my bike stem broke while I was going down a hill at 32 MPH (per my Garmin). The stem is what connects your front fork to the rest of your bike. I was fortunate enough to think quick and dive off the bike into a tuck and roll (people have been impaled). I came out of it with a severely bruised left shoulder and right thumb. The shoulder took my entire body weight. The thumb happened as I rolled attempting, successfully, to keep my head from impacting the pavement.
Now intuitively you would think the shoulder would be the longer to heal. I was actually back on the bike 3 weeks to the day with the shoulder at about 90% and 100% within two weeks after that. The one caveat being that I had to pull over to hydrate for over a year because I'd drop the water bottle with the bad thumb and didn't trust it enough to hold the handle bars while hydrating with the other hand.
I was doing the hand squeezer (cutting people off from the masterbation jokes in advance) to build up strength in the thumb that entire time. Even if he's "only" out 6-8 weeks this has the potential to linger for a lot longer until he has full strength back in the thumb. I couldn't have gripped a football for a long time. I'm sure he'll have every specialist and physical trainer looking at it getting better care than I did but still.