Parent with cognitive decline

Hi everyone, wasn’t sure where on Reddit to post this so please redirect me if needed. I wonder if other millennials are dealing with parents developing cognitive decline? My dad has been dealing with it for a few years but this year it seems to have really gotten worse, and he forgot to get my mom a birthday gift or organize any kind of cake, and forgot to get me a Christmas present. It’s not about the presents and I don’t mean to sound entitled, but he has never done this before so it hurts to see the change. I know it’s not his fault but I’m having trouble seeing past my emotional response. Thanks in advance for sharing any advice, resources, or any other communities on Reddit where it might be appropriate to share about this.