I hope your kitty is ok. My Fred had dementia when he got up in years. He had also had a head injury when he was about 7, so he was also a little goofy from that. If your kitty does have dementia, one thing that the vet recommended was that we not change anything in his world very much. Familiarity is very good for him.
Fred lived to be 18. He was still happy and loving, just a little goofy. We had to keep an eye on him so he would not forget things like where to litter box was located, and remind him not to claw. Sometimes when he woke up from his nap, he would seem to be disoriented until one of us went to him or he realized he was in a familiar place. I would try to put him in one of his usual spots if he fell asleep somewhere else, so he would know where he was and not get upset and cry. The other cats were pretty good about running to see about him if he cried out. He was a good daddy cat. He cared for them when they came here as terrified rescues, and they cared for him when he grew old.
It is possible for a kitty with dementia to live a happy, health life, I hope your does.
Please excuse me if this post is a little rambling, I just woke up.