As a former caregiver of Alzheimer patients, I've seen what it does to the families. When a loved one doesn't recognize you it can be devastating.
Some families don't really understand the disease itself and they ask doctors, nurses, etc. "Why can grandma remember what happened 30 years ago but she doesn't know my name?" It's heartbreaking to watch small children with their grandparents. The child wants the love and attention they remember getting from grandma or grandpa, but, the elder doesn't know who they are looking at- which, in turn, confuses the child. Try to read everything you can about the disease. It will help you understand what your loved one is going through and it will you get through it a lot easier. My prayers are with you.