Bike adjustments notwithstanding, you should sit around and wait for it to heal no matter what. Some pain is pretty normal, especially if you suddenly ramp up your weekly mileage like at the begging of a tour you didn't properly train for (did you guys train?), but if your brother's situation is what I think it is, you need to wait until he can ride relatively pain-free, even if that means forgoing part of your trip.

If you try to ride through this, one of you might wind up with an injury serious enough to warrant surgical intervention.