Hiya Lizzybean,
So sorry that your mum and you are having to go through this. This was the beginning of the end of independent living for my mum when she broke her shoulder. I think the struggles just brought her dementia to the attention of those who hadn't shown much interest up to then. As mum lived alone and we were down south at the time, they readmitted her to hospital so they could keep an eye on her rather than struggle at home.
A couple of bits of info for you. Mum too was bruised from her neck to her fingertips. Arnica was used to clear the bruising and certainly seemed to work. Like your mum, she never remembered falling or that her shoulder was broken. Collar and cuff? Never! Sooo, the consultant said it was time to revert to the old fashioned approach and they used an old fashioned sling to hold her arm close to her body and then put her clothing on top of that. That seemed to work quite well BUT it did make her less stable if she chose to move so they made sure someone was with her when she was on the go. She was on painkillers but not too many. The consultant said this was for 2 reasons, so she didn't get groggy and have another fall if she went on the move and also he said that a little bit of a twinge if she tried to move the arm was a reminder not to do it. On the days she was really agitated about the sling they would use a pillow and make her rest her arm on that. According to what we were told, the aim is to make sure that the shoulder doesn't drop as it heals as this could cause problems in the longer term and make it more susceptible to arthritis. Luckily, mum's shoulder healed just fine - not in any way due to her having been careful I might add!
In addition to the carers it might be worthwhile (on the basis that this is a medical situation that requires medical input) to contact her GP and to ask if the DN could call and check on your mum over the next few weeks until the shoulder is healed. I would argue that whilst carers are fine, they are not qualified to recognise or treat any issues eg pain. I'd also point out that with her dementia, there is a danger that without the input from DNs that she may well have to be admitted to hospital in order to get constant supervision.
It is gonna be a long 6-8 weeks isn't it. I hope you both get the support that is needed to see you through this.
Fiona
Mil has a painful shoulder, damaged after a fall over a year ago, and things like hoovering cause her a lot of pain - but she can never remember. Because I'm here with her, its just a matter of constantly reminding her - but with something like a broken shoulder, where its imperative she wears that collar, and where you can't be with her 24/7, has to be a nightmare. I wish I could suggest something, but I honestly can't think of anything that would stop her removing it, and acting as though the shoulder wasn't broken 
