By now he probably finds it all unbearable to deal with and he just doesn't feel comfortable being in your parent's house while you, yourself, are not comfortable. So, unless that dynamic changes then I don't see why he'd ever look forward to it and he likely can't give you a straight answer because you are pushy and do not take no for an answer.

If you do want to reiterate it, then by all means but be sure to carry that same energy for your parents.

But aren't you using your boyfriend as a coping mechanism as well? You are literally using him as a shield just because you are unable to stand on your own two feet vs your parents. He's clearly uncomfortable and you are trying to force him to do things he doesn't want to do and much worse, YOU don't even want to do it. No one wants to be a scapegoat in a relationship so I don't blame him for not wanting to go. How this how you intend to live your life 10 years from now, when you have kids and plan to grow old with him?

How can you even compare the drummer to your situation? Because one is clearly a vacation that they both will and want to enjoy. You mentioned all the reasons why you want your boyfriend around none of them included anything about his feelings nor that you both would enjoy being there. You've got to do better if you want this to work out.