Watching my father forget me...

My father is my hero. I love him more than anything. My mom was a completely abusive piece of shit who will never be in my life no matter what. My dad fought hard for custody of me and when he won he did everything in his power to make sure my mom would never hurt me again. I'm a daddy's girl and will always be. My father has dementia now and I'm completely destroyed. My step mom has been caring for him. I went to see him today to see how he's doing and this was the first time he completely didn't recognize me.... He kept asking who I was and when I said my name he didn't know who that was... Who I was... I went to my car and cried. My boyfriend hugged me, but honestly all I wanted is my dad... I'm fading away from his memory. All the good times we had together. Every memory we've ever made... He's losing them... He does know who I am and I'm scared he will die completely forgetting me..