This is not psychological advice. If you are inclined to make a transition in how you think and behave, consult your doctor or a licensed mental health professional. My suggestions are ones that I believe have worked for me. They may or may not apply to you and you will not know if change is a good idea or not for you unless you consult with a qualified medical or mental health professional.
To live better and to live well, you probably need to make the transition from thinking how things were or could have been THEN and deal with the fact that this is NOW and no amount of wishful thinking is going to make things the way were before dementia hit you or someone for whom you provide care. It will never be easy for anyone to deal with dementia but you can probably make a transition if you are willing to let go of the past.
A few issues in making the change are in the mind map below. Click on it to make the map larger and to zoom in.
Note. PWD (or pwd) means person with dementia.
This presentation focuses in on parts of the map above. It will run automatically. If you would like to go through at your own pace, hit the pause button and then the arrow keys to manually move among the slides.