I say keep being civil and respectful, but don't think that anything has really changed. It's always possible for people to change, but at this point, that would be a long process.

My DH does what I call "good boy mode" where he acts very normal, sometimes after acting like he's not even in his body. It makes me feel like I've lost my mind at times. It now seems a bit like a manipulative part of the cycle. He can be several different people during a 24 hour period. It was DD who said, "eh, just wait a few days and it will change again.". That's like a mantra around here now. If he ever changes, it's going to be proven over a very long term. It's okay to enjoy the moments of calm, but don't fool yourself into thinking something has changed in a deeper way.

I felt the changes in my DH were so significant, I couldn't accept it. I'm a member on another board for people who have loved ones with frontal temporal dementia (ftd). It's a behavioral variant dementia that tends to start earlier than others. It is extremely hard to diagnose because it affects temperament and behaviors long before it affects memory and ability. Somedays I think dh is a covert passive aggressive narcissist who collapsed completely, and somedays I think he has ftd, and somedays I have no idea. For the most part now, I manage interactions with him while trying to prioritize my and dd's mental health and well being. Don't know if I'll ever know, or what will happen between here and the train wreck that has to be coming at some point.

Hope you get your bed built. I can certainly understand feeling so down that your motivation is gone.