You are right about that.
So here's my suggestion, for what it's worth: maybe work it so keeping the store opened is HIS idea, not yours. I'm not sure how you could do this but if he thinks it's your idea, he's def against it right now.
We say white, they say black.
We say stay, they say go.
Keep being supportive though. I think that's great and great for your son for you two to be at least civil to each other.
Good things can grow from there.