How to tell mother about her husband's death?

We often speak of the “Theraputic Fib” on this site. That means, in order not to upset someone who no longer grasps the concept of death and dying, that their loved one is “visiting someone”, “might be by later”, “will come with us next time”, etc. Unfortunately, trying to get someone who suffers from dementia to grasp that they will never see their loved one again is a futile attempt. You will have to keep re-explaining it. Mom doesn’t remember Dad’s Service and if she does, she may think it was one of the many others she’s probably attended in her lifetime.

It’s ok to use the TF. We’ve pretty much all done it with our loved ones at one time or another. Don’t feel guilty. It’s really the kindest way to save them from becoming upset.