I can relate to some of what you are saying.

My mother has never wanted to have a computer, instead relying on me to find out information, order medication, fill in forms, etc. She doesn't have dementia, but often panics which causes confusion. Between us, we're trying to get help for her by receiving social care payments. Done one form, now waiting to complete another. Also reliant on me to take her to medical appointments.

Sometimes, she's very confused. When I get to the bottom of it, usually because she hasn't drunk enough water or eaten frequently (borderline type2 diabetic). She's freely admitted that food doesn't interest her, so keeps stalling when I offer to batch cook.

As for my brother, well he's not helped. I believe it's time to talk about lasting power of attorney, but dread raising subject with him because of his manipulative wife. He's always been her favourite, because he says the right things.

Get all the help you can. Many unofficial carers have health problems because of coping with these situations on their own. It's difficult not to lose your cool. The number of times I've bitten my tongue, should be full of holes!