Having had both my mother and my Fil with dementia, I do know how upsetting such things can be. My normally robust and jolly brother was once reduced to tears because of the vile things my mother had said - and he had always been the ‘golden’ boy.
You just have to keep telling yourself it’s the disease talking, it’s not personal, however much it may feel like it at the time.
Your employers really should have given you some training in caring for people with dementia. Contrary to what so many people with little or no experience often think, all too often it’s not just a case of gently getting more forgetful. O would that it were!
One thing I really wish we’d known when we were new to it all, was not to correct people when they say things you know can’t possibly be true - it’s true to them, so you just have to go along with it whenever possible.
E.g. when my mother heard any country from Armenia to Zimbabwe mentioned on TV, she’d say she’d been there.
By then I knew better than to say, ‘I don’t think so!’ Instead I’d say, ‘Oh, yes - was it nice?’
The answer was invariably ‘I can’t remember.’ (!)
More seriously, a good ten years after MiL had died, FiL suddenly started asking where she was. Still new to it all then, we gently explained that she’d died years ago, but he’d cry - only to forget and ask again soon afterwards.
So we started saying she’d just gone to the shops, or to visit Auntie So-and-So, which would keep him happy. He never remembered that we’d said much the same before.
Similarly, my mother at over 90 started saying she ought to go and visit her parents - dead some 30 odd and 50 odd years - since ‘they must be getting old and could do with some help.’
I’d say e.g. ‘Maybe tomorrow, then, but I’ll ring first to make sure they’ll be in - we wouldn’t want to go all that way and find them out, would we?’
I became very adept at what is known as ‘love lies’! As long as they kept her reasonably happy.....
I do wholeheartedly recommend the Alzheimer’s Society Talking Point forum for carers of people with dementia. For several years it really was a lifeline for me.