some sort of creature

That list might say things like “Paint a picture. Go birdwatching. Finish that great novel I started reading. Call my grandma. Learn to bake a cake. Visit my sister. Play piano.”

you have to be kinder to people who are slow processors.

you have to be kinder to people who don't understand your jokes.

you have to be kinder to people who forget important dates.

you have to be kinder to people with cognitive decline.

you have to be kinder to people who were always this way, too.

the way you frame your conversations is important! People with dementia are often, particularly at the earlier stages, very much aware that their memory is getting worse. This can make them very anxious, which isn't fun for anyone, least of all them. One of the most common things that people say to people with dementia is "do you remember ___?" as a way to try and prompt their memory. This feels helpful, but it's not. Because hey, in all likelihood, that person does not remember ___, and being confronted with this fact is not going to make them feel great. Remember that they literally have a degenerative brain disease; they're not going to suddenly regain their memories because you tested them. Instead, try talking about your own memories. Tell them what you remember. Tell it like a story. If they remember, then they can join in. If not, then hey, it's a nice story.

don't correct them if they say something wrong. Their version of reality is not going to be the same as yours. That's just a given. My grandma is often convinced that she's just on a very long holiday in a nice hotel, and that her dad is waiting outside in the car. I'm not going to tell her "uh, actually, you're in a care home and your dad died 50 years ago," because who's that going to help? Quite literally no-one. It'll just confuse her more, and she's already confused enough. Even if the person is saying something that's making them anxious - a common one is believing that people are stealing from them, or that someone is being unkind to them - then it's easier to try and distract them by trying to talk about something that you know makes them happy, rather than to outright tell them that they're wrong. Being consistently told that they're wrong can make them react defensively; they're not children, and they (usually) know it. It's just easier not to get into a confrontation.

get used to repetition. Don't get frustrated when you have the same conversation 25 times in two minutes. It's going to happen. For them, it's the first time you've had that conversation; they won't understand why you're angry at them for asking a question. It's completely normal to feel frustrated, but the onus is on you not to make it their problem. My grandma's short term memory is, charitably, about 3 seconds long. A conversation with her at this point is like rehearsing for a play; I know her lines, and I know mine. That's just how it is. She gets just as much joy out of telling me that she likes my cardigan for the 86th time as she did the first time she said it. People with dementia are not able to retain the information or the memory of that previous conversation; reminding them that you've already answered their question is just going to confuse and upset them.

don't take things personally. They might say things that are unkind. They might say completely inappropriate things. Again: their brain is deteriorating. It is a medical condition. They're not becoming bad people, or showing their 'true selves' to be evil and rage-fuelled. It's a combination of the fact that they're living in a perpetual state of confusion, which can lead to frustration and anger, and the fact that their ability to process and respond to information is affected by the dementia itself. If they say something cruel to you, you just have to take it on the chin and recognise it as a symptom of a disease that they're not able to control. Step out of the room for a moment if it gets too much. I've been fortunate in that my grandma has never experienced this symptom, but it's very common, and it's no reflection of you, or them.

don't treat them like children. My grandmother is 92 years old and she will look at you like you're the bane of her life if you try and tell her what to do, or use baby talk. Keep your sentences short and clear to avoid confusion, but don't ask them if they need you to clean their wittle fingies.

try and avoid open-ended questions, especially ones that involve memory recall, like "what did you do on the weekend?". My grandma was an absolute queen at making shit up when people asked her that, because she couldn't remember a damn thing, and she never liked to admit that she couldn't remember, because it made her stressed and anxious. "I picked up leaves" was her personal favourite, for some reason. I used to just tell her about my weekend instead, and sometimes she would joyfully tell me (completely falsely) that she also went to the shops, and that was much less stressful for her; she wasn't actively trying to come up with an answer to cover for her own lack of memory, and instead felt like she was part of the conversation on her own, equal terms.

most importantly: don't try and pull them back to reality. The best way I've learnt to communicate with anyone with dementia is to enter theirs instead. Sometimes, this is referred to as 'validation therapy'. It's about acknowledging that the reality of someone with dementia is as real to them as your reality is to you, and you're not going to be able to 'reorient' them to your version of reality, because they don't have the short term memory or ability to retain information that would enable that. Put simply: if my grandma asks when my uncle is going to come home, I gain nothing from (correctly) informing her that he's dead. This just upsets her, because every time she hears it, she's receiving the news of his death for the first time. That sends her into a spiral of grief and anxiety that remains even after the memory of his death has vanished again. Instead, I just tell her that he'll be home after lunch. She nods, accepts it, and we're both happy. My uncle is still dead, but in her world, he's going to come home soon. It's a way of having empathy for the person with dementia, and acknowledging that your reality, or objective 'truth', is not more important than their wellbeing.