Nope, not progress. Now you should go back and tell him you don't want to go after all because you came up with something better to do.
Understand this: He does not want you there. He just decided to not completely crush your feelings by saying as much. Yes, they are monsters and aliens in their current MLC or WAS fogs, but parts of the "real and old" them exist. And it was the "real and old" H that didn't want to hurt your feelings and gave you the lame excuse of not wanting too many people in his car.
You may want to go to this event, but he obviously doesn't want you there. So screw that. You take advantage of the day off from S and go do something for you, even if it's just sitting at home relaxing. Clean some more cat pee, I don't know but do something for you, just for you and don't mope.
You see positive results from distance. You've learned this over and over with your H. Then, you get that positive response and go running to him and push for more. Instead this time, give distance again. Get your positive response but this time give MORE distance and maybe see if the next positive response isn't even bigger. That would be my next experiment.
You said you "won't push if it's a problem....". You did push and it was a problem. I would have asked him "Hey if you want I wouldn't mind coming with you to help out with S in case you and FIL want some male bonding time....if not, I have some things I could and need to get done, but it's not urgent."
You pushed and he shoved back. Let this one go and work on some distance which you've seen positive results afterward.
