Here to say how much I love this post! He will do well under relaxed environment with his speech. Stutterers tend to stutter more under stress. Just let him be. Don’t finish sentences for him. Let him take his time. My child gets “blocks”. He can’t get a word out for a few seconds and that’s ok. You need lots of patience and honestly you will get used to his speech. I do not think not having humor has anything to do with his stutter. Almost seems like you are still getting to know each others. He seems like a wonderful guy kinda hard to find these days.