When an individual has gone through the special tests and meets the criteria set out for dementia diagnosis their will be catalogue of feelings flooding their senses. It can start with denial, that is is just not true, it can not be happening to them. Then a feeling of shock, anger and they might be very frightened at this stage. This can lead to acceptance of their diagnosis in the best scenario.
There is a lot of help and advice on this subject. Here are some I have found on the internet;
Alzheimer's society is a charity that gives information