Mum has arthritis in her hands. We have had to change door handles etc (after she had to phone me to get out of the bathroom) but I worry about her managing with the fire which she loves. Sp have put coal in small plastic bags so she can just drop a mini bag into the fire. It stops her struggling and even keeps her hands clean. However, I really don't like burning plastic. So, I figured a strong paper bag would do it. I have access to a cash and carry so can get a box of paper bags, any recommendations as to which kind?
While I laud your attempts to allow her to continue with the fire she loves, I think I would stop attempting to do it. Coal fires - which I've lived with for most of my life until recently - are not in my view suitable for an older person with such bad arthritis that they couldn't exit their bathroom unless there is no other option or they have someone to assist hour in and hour out.
They require constant maintenance, are pretty inefficient and are dirty. The dust alone would put me off but the emptying and clearing of cinders and ashes just makes it not worth it - they might look great when freshly going but coming to them of a cold morning, grey and full of clinker - even if they've been smoored the night before - would have me close to weeping if I had bad arthritis.
Is there any possibility that she could go to a gas fire? It may be time for something like that for her and I suspect that her situation would be better served if you helped her to acclimatise to that fact rather than assist her to (vainly) keep on going as she has. The arthritis won't improve any.