You know, that time of day? That is when the cortisol secretion is the second lowest for the 24 hr period.

This is when pain, may become more prominent, or other symptoms of inflammation. I'd ask your hubby if he is in some kind of discomfort, to make sure there isn't a medical reason for his being crabby.

There is a serious medical symptom called sundowning. It is associated with Alzheimer's dementia, and is the depletion of some neurotransmitters, that run the brain. I hate to bring this up, but one should consider if everyday, he runs "down" like this. If you tell a doctor they will test for early onset Alzheimer's most likely. I would keep this to myself and not alarm him. (I don't share scary things with my husband as he is doctor phobic). I have some supplement tricks that may help if it is just fatigue or pain however.

Men don't like to talk as much as women though. This is one reason I think cats are so good for us as we age. My kitties put up with lots of chatty venting with me, in fact!
I've got this new kitten, who is currently in my avatar. She is extremely gifted for communication. She will now shake her head and flick her paw when I ask a question and the answer is "no". She has just increased this behavior.
example: Want to go out? She'll check the temp and whether it is raining or wet, and if too cold or too wet, she shakes her head and if extreme will shake her paw. I've seen her do it outside too, when something displeases her. None of our other cats react to questions like this...so it just must be HER talent. I find it cute, that I get answers back sometimes. Granted they are feline answers, but they are answers of a type! I am beginning to call it the "ick" response! LOL