Children handle these types of things differently and can have widely varying reactions, depending on their age, upbringing and personality. They also will devise different ways of coping.
But no matter what the age, be honest with them — at a level they can comprehend. Then let your grandchildren talk openly about their feelings. Having someone you know and love with dementia causes grief — in all age groups. A part of a person you love is vanishing and changing each day so it is natural for someone close (of any age) to experience the grief process kicking in.
If you are not comfortable with talking with them about Alzheimer’s or letting them know about a new diagnosis, have someone they trust speak with them about it. This might involve using the services of a licensed counselor or a support group, depending on the circumstances. This is a stressful family dynamic and must be handled with care. Everyone is experiencing grief, anxiety, loss, change and, eventually, death.
The national office of the Alzheimer’s Association has excellent information for children on its website. Visit it here.
There are also many fine books available on this subject. You can find various titles available for everyone from young children to adolescents. They also can be found at the Alzheimer’s Association website
Many online book sources. Suitable publications also can be obtained from the American Health Assistance Foundation.