Why is “I was told you’re a genius, so tell me something genial” a bad question, and how do I explain that simply?

I (32F) and my brother (26M) were talking about how some questions are so obviously bad that the best move is not to answer at all. To make the point, I used an analogy: “This is like asking, ‘I was told you’re a genius, so tell me something genial.’” I meant it as an example of a trick question with no rules or way to pass. For those who get the reference, yes, this was in Malcolm in the Middle.

He didn’t take it that way. He said, “I love deep questions like this. I can’t answer it because I’ve never said I’m a genius, but I’d love to hear what Elon Musk would say. If I were his level, I’d know the answer immediately.”

I pushed back and said, “You’re kidding me, right? This question has the depth of a kiddie pool.” He got upset. He says I was insulting him for liking “deep” questions, and that this is the reason I’m still depressed at my age despite years of taking medication, and have not gotten over mom’s death from three months agai like he did, that I always think I’m better and smarter than him even though I ‘completely lack curiosity’ and because I never ask people directly to get to know them, only though boring indirect questions, and is now giving me the silent treatment.

Yeah, this is serious.