You could say, "H, I think we need to work on S4's manners. What do you think we could do to get him to be more courteous?" --------------------------------------------------------------------------------
I've tried this. H stands by the idea that my son adores me and I am reading too much into his actions.
I saw that coming, I hate to tell ya.
Throw down the gauntlet. Kid disrespects you next time, and you say to H, "Well, don't just sit there like a lump! Your son just disrespected me. When are you finally going to do something about it?!!!"
And if H tells you you're reading too much into it:
"Don't YOU tell me what I should think and feel! Son is showing me blatant disrespect and this has gone on long enough! If you're not man enough to discipline your son and respect my feelings, then get the f*ck out!!!"
I wonder how he'd respond to a show of strength. Betcha he'd power struggle with you. But to me, that's an indication... someone who truly wants to have a great relationship, cares deeply about you, respects you... they're going to be concerned about your feelings, Heather, and will want to make sure you're OK. They're not going to argue against what you're feeling and treat you like you're insignificant. How he responds says a lot to me that I don't like.
So I say throw down the gauntlet. That is to say, challenge him to rise to the occasion. Appealing to his higher self to do the right thing might... might... get him to do the right thing. See what happens, and judge his actions accordingly: Is he with you or against you?
P.S. Good for you with your quality time with S. Do more of that and win him over