This is not an uncommon fear. We fear for our own abilities as well as aging friends and family members. Who are we without our memories?
I suppose by the time most of us are aged enough for Alzheimer's to onset one might be able to take comfort in the idea that our children will hold on to our memories. At least the ones they know of.
My child(ren) won't hold the memories of how it felt to have her(them) fall asleep in my arms, completely trusting, completely comforted. My joys and anxieties can not be shared memories.
It makes it difficult to fully enjoy every moment.
The answer is simple in nature and difficult to implement. Don't live for the future, be in the moment and whatever will be will be. John keeps telling me to put the camera down and just enjoy it. I try and often I fail. Is this why first children have their picture taken so frequently? By the second are people just too busy to feel these anxieties? What about the third an fourth? Are those special moments similar enough between all babies that once you experience it twice you can feel comfort that they are burned into your memory?
At the end of the day and the end of our days we must relinquish these private memories to the next generations. Their experiences will be similar and familiar. Babies don't change that much in a hundred years.