Sling pattern?
 

My mother in law fell and broke her arm ( very close to the armpit) this weekend. Any movement causes her a lot of pain, and the cheesy sling they gave her ( apparently they aren't going to set it) doesn't give her much stability. Has anyone made a more substantial sling that would keep her arm from moving? Thanks!

Before you immobilize it, please check with her Doctor(s).
It could be they want that little mobility, as a semi-therapy.
While movement is painful for her, the thought may be that as an adult, she will minimize the movement ... and that some movement is needed during the healing process.

Immobilization could cause everything to lock up ... and her to lose total long-term mobility.

I know you don't like to see her in pain ... though be sure that the actions you take are for her good, and not create a further problem.

Thanks so mentioning that - I had not thought of that - just that she was in pain. I'll keep it in mind as I look for a pattern.

I hope it helps and that you will check with the Doctor(s) ... I mentioned it, as I know of another lady who the same thing happened to, with much the same treatment (or as we see it non-treatment). Sadly she had to suffer some as she learned to minimize the movement to keep the pain to a minimum ... and is now doing much better.