It's not a fun thing, or something I would wish on my worst enemy. You see when you have a loved one with Alzheimer's, you could do the same thing five days in a row and they wouldn't remember depending on how severe. Both of my dad's parents had the disease, and not just mildly.
There would be days when my Meme (grandmother) would be fine, she would know who I was and little things that had just happened. There were other days when I would visit her the day before and come back the next day and she would be mad because "I hadn't visited her in months" or on a really bad day not know who I was. There are times when she would think I was my dad's sister and it was 1980 and would cite off my dad's teachers and then ask me about Valdosta, where my aunt went to college. She would call me my aunt's name and it was like you were playing a game. Pretending to be someone, because if not it would make her upset. But either way one of us was upset by the end of the night.
The hardest though was after my Dedaddy (grandfather) passed away. My Meme would wake up at night and have no clue where he was, with no recollection of him having passed away. My dad would have to go and tell her all over again, and it was like she had never known. It would be reoccurring and to me was one of the hardest things.
She never understood why she couldn't live at her house on her own instead of in an assisted living home, and would argue the fact constantly that she would be fine. Although, when she hadn't been she would take incorrect medicine, and reply to almost every piece of mail asking for money and pay people multiple times for one bill.
They both showed signs when I was about nine years old, my memories of them where they weren't effected are very little. Mostly just through pictures, it saddens me that what I said would never entirely clock in their head or that I could say the same thing every five minutes and have a reaction that was still in awe or shock.
Their love to me was clear, but it broke my heart that they may never have had true memories that they remember with me. Although I know they were there at some point. At times it was almost unbearable but then moments shined through and they were like their old self. If you have a loved one with Alzheimer's you know what I mean and my heart goes out to you.