I think the problem is, with help available, that it differs from region to region. My Mum was in the Midlands and the help we received was excellent.
From regular reviews of medication, which as the illness progressed were tweaked, to referrals to a sort of "club" for want of a better word, where she went once a week for about a year, to help with adaptations for the house (safe key box outside for example, because while she was still living alone you can imagine how many times she lost her keys or just went off without them.
Then there was a period of about 6 months when she had a weekly home visit from a team (I can't remember the exact name- attached however to social services)
The GP said to us (and was right) that while the local authorities see that there are family members to do the grunt work, they'll let that happen. Because, obviously, of funding cuts.
I'm in a different country, but had another relative nearby who kept an eye.
It's not an easy journey, and it's still not easy for me to think it- but the best thing for all of us was when she finally went into residential care. Because initially (and this is the fucker about it all) you have this slightly ditzy person getting a bit forgetful, but still going abroad, driving, doing the accounts etc. And you think you can handle it. Then comes the aggression, the hallucinations, the utter conviction that the dead are still alive (to the point of going to their house at 4am and banging on the door) etc etc.
Sorry for the gloom and doom scenario, but I think if I'd known then more of what I know now, it would have been easier to deal with.
Btw, there's a long running chat thread in Elderly Parents with the word "cockroach" in the thread title. A mine of practical information and handholding for those who need it. Lifesaver for me back then.