Let's see, wasn't he racing just six weeks after breaking his collarbone?

So sorry to hear about your DH. Mine broke his collarbone in a cycling accident years ago. I know he wouldn't have felt comfortable doing a LONG ride like that just a month out. I had to mow the lawn for him all summer. Lawn-mowing does use the upper body more than cycling, but anyone who says you don't use your upper body climbing is either crazy or riding a recumbent!

I guess that's a thought...wonder if he could borrow, rent, or buy a used recumbent for the ride, if you really don't want to cancel? Under-seat steering wouldn't bother the clavicle, but a fall onto that side would. I wouldn't chance it.