Should I keep going to my brother's performances when he never comes to mine?

My brother sent me the dates for his next play and asked which night I was coming. I nearly replied, "The night after you finally come to my concert."

I've attended his last three productions. He hasn't come to either of my choir concerts, though neither conflicted with his rehearsals. He says choral music isn't really his thing. Theatre isn't especially mine, but I go because seeing him on stage matters to him.

He does support me in other ways. He has picked me up after rehearsals and asks how they're going. I don't want to erase that because he hasn't sat in the audience. Still, when the concert finishes and everyone is finding their family, I notice his absence.

Is it fair to tell him attendance matters to me before deciding about the play? I don't want a ticket swap disguised as affection, but I also don't want to keep calling something unimportant when it hurts.