I (F18) told my brother (M26) I was angry with him because I texted him and he didn’t respond for 9 minutes and he was mad

I tell my brother everything so I texted him I was angry with him because I texted him and he didn’t respond for 9 minutes. He said it’s not a big deal. I said yes it is because I texted you and you didn’t respond. Later on, he called me and asked why I’m angry with him. I said because I texted you and you didn’t respond. He said I was in the Car and didn’t see it. I said why didn’t you respond as soon as you saw it? He said I’m not mad at you at all but I’m not going to drop everything so I can respond to your text as soon as you sent it. I said text me back as soon as you can. He said ‘no I’m gonna hang up’. He hung up.