40/m/usa
Your 16yo brother is hormonal and will be annoyed by any threat that might possibly change his friends. So be careful. Talk to your brother about it, find out (not from your brother!) if this other guy likes you. Then go for it. Your brother will get over it in about, oh, 6 years, when his hormones stabilize.
I have a long time interest in psychology, specializing in relationship dynamics for 30 years.
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