AITAH for saying I couldn't be bothered to open a drum program my dad sent?
For context, my older sister is in these drum lessons and is going to play a song live on stage on May 22. I'm extremely happy and excited because I've been saying for years that she would be great on the drums and now that's she's finally got a set she's totally awesome on them.
The stage is hosted by a music school, the same one she takes lessons from. My dad sent me the program about drums—even though I'm a GUITARIST and would gain absolutely nothing from opening a page about drumming. All it says is 'we teach our students this...' or 'at bla bla bla musical academy...' that. It doesn't matter to me because they don't teach guitar nor does the page hold any useful information for all people, just drummers.
He asked me "Hey, did you open the program I sent?"
And I told him "No, I didn't."
"Why not?"
"I mean I couldn't be bothered."
"Why? This is your sister, dude. She's your family you have to show support? Where's the support?"
"I don't need to open a drum program to show my support. Why would I need to open the website?"
"I've been noticing you had a bad attitude these days, saying some bad stuff. You must be depressed or something."
"What???"
"You're acting like a depressed person."
"I just don't understand how not opening a program affects my support for her?"
"You know what, you're right. Why should you be bothered."
He then gets up and leaves. I'm just so totally confused and he absolutely ruined my mood. What did I do wrong? I'm proud of my sister but opening that program is not changing things. Am I genuinely not showing support?