Aw, sorry to hear about your DH. Sending healing vibes!
+1 on taking a wait-and-see approach. Find out now what your travel insurance's limits are, and I guess it would be courteous to find out whether there's a waiting list for the trip itself.
You'll know a lot more after he sees the ortho, but even so, every individual will heal at a different rate and have a different tolerance for pain. I think there's a reasonable chance that he'll be able to ride - and a reasonable chance that he won't.
So the longer he can postpone the decision, the better chance you both will have of making a decision you won't regret.
Speed comes from what you put behind you. - Judi Ketteler