Something happened recently with my 87yo FIL that could help.
My RN niece gives him is B12 injections and she noticed he wasn't taking his medicines. She asked and found that he had used all the pages in the booklet in which he had been keeping track of the medicines he takes, so .....he stopped taking his meds.
Who woulda thunk it?
For your Grandmother, get a book (with many pages) and one page per day, record what she gets and who gave it. With the possibility of multiple people caring for her, there HAS to be one repository of knowledge and record of what is taken.
With the arm, can you find some front closing house dresses? And if you sew, enlarge the arm hole and make it easier to put on. Depending on her mobility, the addition of flaps with velcro closures might be a help.
Does her bathtub have a hand held sprayer? I know Home Depot and Lowes have some that can replace the usual shower heads. And a waterproof seat for the tub/shower stall so she'll feel secure and not worry about slipping.
If she's a TV watcher and used to her remote, make several slings with pockets for the remote.

That she fell implies that there is a potential vertigo problem. One of the causes of vertigo in the elderly is Pernicious Anemia, which happens when our bodies stop absorbing Vitamin B12. This comes with age for a large percentage of the population. For my MIL it wasn't diagnosed until she was about 80, although in retrospect she had had it for at least ten years and it wasn't diagnosed until she was Stage III. She was seeing a doctor for that decade and it just got missed.
Your grandmother needs to be tested for this, because she needs to feel as if she won't fall again.

I'm sorry your grandmother's hurt.

Gardenweb's "sister site", That Home Site, has a Care Givers Forum that's sure to have some helpful tips & advice.

keeping you & your grandparents in my thoughts & in my heart.

Here is a link that might be useful: Care Givers Site on gardenweb

Been there, done that, twice. First mom fell and broke the right arm in 2000, exactly the same place you describe, then fell again in 2004, and broke the left arm, in exactly the place you describe. It's the first couple weeks that were the hardest, when it still hurt her a lot. The bones actually healed up and were stronger then before she broke them.

It really helped to remain positive and cheerful and encouraging at all times, and not dwell too much on the injury but use the time for quality visits. I used the opportunity to spend more quality time with Mom, watched comedy movies with her, visited her friends with her, read magazines with her when we went to her doctor, brought her treats, took her fun close-by places like garden centers or the mall on a slow weekday morning, just included her in my errands when she was well enough to go out, kind of turned it into a vacation of sorts, and it really was ok, for her and me both.

It turned out in the long run she was having tiny strokes, that is what was causing the falls, and she died of a massive stroke in '05. So it's good to check on what might have caused the fall, so you can keep her as long as possible...anyway, we had that quality time when her arms were healing. Those times are actually pretty precious memories now.

Thanks everyone for the ideas and thoughts.

Ann, I am going to have to sew up some house dresses that work for her. She really needs a toga or a sari. :-) That arm just can't go through a regular armhole at this point. We did put in a really nice bathroom setup for them a few years back, with a nice seat in the shower, handles, and handheld shower head. I also will check on the anemia angle. There are so many thoughful ideas in your post.

Sylvia, that will be a good link for me to look at. The support helps alot.

Hoov, I am really glad you posted about your experience with this injury. My grandma has been having mini strokes for a long while, but this unfortunately was caused by her oxygen cord 'hobbling' her as she hurried for the phone. Having a positive spin is very helpful, and it's good to hear your perpective. My grandma offered to stay in a nursing home for her rehab - she just hates not being independent - but I can't imagine sending her away from her home. Hopefully we can get through this first week or two and things will get easier. Glad to know the pain level can decrease in the short term.

- Michelle

Michelle, prayers and helpful vibes coming your way, and I'll post ideas when I'm not so scattered [totalled my car!]

I agree with Ann 110% about Pernicious Anemia. I have it [rarely at my age] and my Gmom and great Aunts had it but I was entirely unaware of that [they were treated early]. Untreated, it is a little slice of danger not to be ignored but docs don't think of it as often as they should. Just a hip shot of b12 saves lives and nerves and the tests are so cheap, too. Do ask, please.

I did help with my mom when she was so sick, so I'll clear my mind and offer suggestions later, but you'll do so great :)

Right, I remember about the arm not going into shirts. I cut the side seams and sleeve seams out of 2 (one to wash, one to wear) of her old blouses and sewed in velcro and I would just put the shirt over her head and velcro them together under her arms. She could move her arm the inch or two it took for that.