My Mom has dementia and her eldest son(my brother) passed away last week. WE all know that he is at peace, but Mom just dwells on the sadness. The dementia makes her forget until she goes to sleep and when she wakes up she asks questions all over again and sobs. She takes a low dose anti-depressant, but I an exhausted.
You have told your mother the facts. That was necessary and important. I'm not sure it is necessary or helpful to keep repeating the message. When she asks questions in the morning, perhaps the kindest approach would be a bit evasive.
"How is Son today?"
"He is having a good day. He has less pain." or "He is having a peaceful day."
And then perhaps changing the subject to something more cheerful. "You know, I was thinking yesterday about the time Brother played that trick on you ... He certainly does have a fun sense of humor, doesn't he?"
It is perfectly OK for a parent to be very sad at the death of a child. Your mother's mourning is appropriate. But since her cognitive level may not let her gradually move forward toward the acceptance you have achieved, I think it may be better to avoid the repeated shock of hearing over and over again that her son has died.
Perhaps she could take a higher dose of the antidepressant, but really, grief and mourning are not the same as depression so I am not sure that would help.
Help her make a scrap book. You get get this out and show her all the happy pictures. May be have a piece at the end of him in heaven (or somewhere beautiful - like a garden) Play some peaceful, happy music quietly in the background.
After all of this put on her favourite dvd or a funny cartoon.
Good luck
She needs to grieve and this will be a slow process for her (and you) While she is looking at the pictures, take a little break, even if it is only sitting in the chair with your eyes closed.
What are the type of questions that your Mom is asking? This will give us a better idea on how to approach this issue.
My deepest sympathies and condolences. I am very sorry for your loss. I know its incredibly hard to grieve yourself but also see your mom suffering as well. I don't know if a grief counsellor might be able to make some additional suggestions.
I hope friends and family can give you additional supports and provide some respite during this difficult time.
Thinking of you.