My best wishes for his recovery. Sounds like his attitude/intestinal fortitude, along with advances in medicine, will give him a great chance.
My brother doesn't even limp unless I kick him....and his injury was pretty grim; he ran over his own leg while motorbiking off-road. Much as I love to give him shizzle about it, more bad luck than stupidity - hit a buried root while taking a muddy trail corner with his foot out for balance. If it hadn't been for his leathers & shin guard, we'd have his foot pickled in a jar. Even so, it was closer to a year before he was really stressing it again , skiing, etc. Never fully regained the musculature in that calf, though. A bone shard severed several blood vessels as well as similar ligament damage to your son's, irrc .
Sounds like Hutch's injury might be somewhere between.