I don't see any rational mind described in your interactions with your brother... It's all emotional IMO.

You were emotionally charged and thus behaved the way you did because if you had been rational, you would have taken the time to think at least one or two things thru. Like his friend being suicidal, and how that possibly affected him (and then maybe even try to reach out to him in case he needed you) or becoming aggressive and forcing his laptop shut when he didn't want to give you the attention you sought.

It's good that you're attempting to identify your different mind states, but seems you need some more practice, keep at it, it does get easier with time and practice.