I was the sleep talker. (I don't sleep as well anymore so don't talk in my sleep as much anymore). I would say all kinds of things.
What you are describing with your husband - his sitting up and talking and saying he must have dreamed it - THAT part he wasn't asleep, but what happens is we wake from something in our dream and we have no clue it was part of a dream and not reality, and we are not fully alert- ... so drowsy.... and so we drift right back off leaving our poor spouse wide awake and wondering.
I used to even be able to fall asleep at night while answering some question or other and my speech would just turn to babbling and my husband knew I was actually asleep (lol - no insomnia problem for ME!)
And yes, I would laugh out loud at funny things happening in my dreams. In the mornings, if I'd just been dreaming, I'd have leftover feelings of laughter or irritability, depending on what I was dreaming.
I could semi-wake up like your husband-go right back to sleep, and right back to dreaming.
Us sleep talkers really are sorry for disturbing our spouse's sleep.... I am glad my husband thought it was funny. He'd tell me about some of it. Sometimes I'd even wake myself up with my own shout or something.