OldMeg when you are first diagnosed with dementia, it is already too late! I went in with my M&D for her first diagnoses at the hospital, when the doctor said those words, I thought my mum would wail, but she didn't react! When we came out my dad was angry that my mum had just been written off, with no medication or physio or anything.
My daughter always says to me if you get it mum, I'll top myself when I get to that age I know my mum, without doubt, would have wanted to go after the first diagnoses, but as I said, it was already too late! She was 80 when first diagnosed, so I wish I could have told her, when she was 50 and worrying terribly about getting it, that she had 30 more healthy, carefree years to go. But having said all that, my mum was happy in the care home, enjoyed the social occasions that they had often. I don't think anyone would want to live with dementia, but it creeps up without one knowing 
wot no the spirit doesn't leave the body till you take your last breath.