Hi, Greyhunter!

I had a similar injury in 1989, although in addition to fracturing the humerus just below the head, I smashed the head of the humerus into crumbs.  

The injury could not be immobilized, so I was in a sling with a weight on my elbow for 12 weeks.  The alternative was to have the head of the humerus surgically replaced, but all of the orthopedic specialists involved advised me that I would lose the function in my shoulder if I went the surgical route.  They also advised that I was likely to lose most of the function in my shoulder as a result of the injury, because the immobilization required to heal the fracturing would create a frozen shoulder.

However!  They were wrong, fortunately!  I did spend the 12 weeks in the sling with the weight, then I was allowed to let the arm hang for 10 minutes twice a day for 2 weeks, then 30 minutes, then an hour, etc.  2 months after that the sling was gone completely and I was sent for physio.  I never went to the physiotherapist, the timing was just too difficult, so instead I started grooming horses.  It took both hands to start, as I had no control of my left arm at all, but within 2 weeks I could brush horses independently with the left arm.  I started riding again then, on something relatively reliable, and have never looked back.

I regained total function in my left shoulder.