I just put down my terrier for dementia. It only gets worse and worse. I didn’t sleep for 18 months, it was a very difficult decision. My old guy would start barking at 6pm and did not stop until 1am when he would start to pace and was in discomfort, he would get stuck at a wall or even an open door. I was paying over 600/month on medications for various health stuff an old dog gets, I fed him home made chicken because it was all he would eat, and I didn’t sleep at all because he was managing ok physically but the dementia became too much. He would sleep all day and then get up at 6 and bark like an intruder was trying to get in except it was me, my husband or kids just living our lives. He started to pee everywhere, in his own bed, on my pillow, sometimes while he walked. One night I was up with him while he paced and when I reached down to pet him to try and calm him, he bit me pretty badly, he didn’t recognize me and was afraid of me. That’s when I knew. Anyway, I waited too long I think, I know my dog would have hated to be confused and agitated and anxious and miserable, he was a very proud dog.