This is the problem isn't it? As people get older, sometimes their understanding diminishes, and they think they're coping, when the only reason the wheels are staying on is because of the help that they are receiving.
As@MichaelandKirk has pointed out, the choices of elderly parents often come at a great cost to their children.
In conversation with my mother, we've established that her fury about having carers was more fury that this is what her life has come to. She was railing against old age and infirmity. I know that she is reluctant to drink because she fears incontinence. She's terrified of falling, but has not the cognitive ability to understand that dehydration is likely to make her fall. I'm trying to protect her from herself, but her desire to 'do it myself' makes her more vulnerable, not less. And she has every right to decide for herself. I've done a lot of work on my own anxiety levels, because those, I can control. More or less...It's very clear that I can't, and shouldn't even try, to control her. But it's hard as hell to have every suggestion batted back.
I hope @Fusby is able to have a productive conversation about getting someone in to fix the roof. In our situation, we have had to tread on eggshells as she insists on trying to arrange things herself because she won't admit to getting in a muddle. Important things stall for weeks while she 'can't get through to anyone' or then when she does, she can't understand what they were saying,or she gets offended at something they say, and puts the phone down on them. So telling OP to 'just' do this or that is likely unhelpful, as she's probably posting on here as she's running out of options.
I think too, it's often the daughters of the more 'chronically resistant' who find themselves here, as there are plenty of other elderly people who have considered how they will cope as they age. I'm approaching sixty and having also worked as a domiciliary carer, I am very familiar with how these things can play out, at both ends of the planning spectrum. For myself and DH, we plan to downsize, and a bit of 'swedish death cleaning', and complete our POA soon. And also considering ReSPECT forms, so that we can remain independent as long as possible, and not cause our children more headaches than they need.
I don't think anyone who's never seen how these things look towards the end of life; the falls, TIAs, confusion, loss of continence and mobility etc can fully appreciate how difficult it can get, when they are adamant that they are staying put come what may. It's absolutely exhausting. Even when we love them.