Your guests have most likely figured out that your h is going thru something. They are intelligent people and can connect the dots. It's very difficult for him to "act" like the old h right now and he's going to avoid, as much as possible, being w/people who knew him and expect him to be the old h.
As for the meet up with his MLC bestie. My xh did the exact same thing. His eyes lit up, he became so happy and his body language completely changed. Back in my presence and the presence of others...yep, like a pallbearer once again. Now that my journey on the MLC path has ended, I can sit back and observe this "flipping". I have found it fascinating to observe this behavior because it just happens and it's not thought out at all. Please do not take it personally.
Just a few more days and things will settle down once again. I do hope that you and your sons have been able to enjoy your visitors in spite of your h's behavior.
At some point, which may not be any time soon, you will need to decide what you want in life and also for your sons. You've been a trooper throughout all of this, but there will come a time, if he doesn't start making some strides to grow up, that you will need to decide what to do w/the rest of your life. You will know when that time comes...until then, live your life to the fullest the best way that you can.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.
