My brother and his thoughts about another girl
I have an older brother who's 23. Even though he's older, he sometimes doesn't think clearly or do things right. He's been with his girlfriend for five years, but he told me a secret. When he was in high school, there was a girl who was in love with him, even though they only spoke for a few months. A year later, he told me he can't stop thinking about her, even though they lost touch. He dreams about her, thinks about her, and sometimes thinks he should be with her. He's asking me for advice. I don't know what to think; he says he thinks about this other person involuntarily, so to speak. What advice would you give him? I don't know whether to talk to his girlfriend or let him figure it out himself.
P.S.: He's been thinking about this girl for over three years WITHOUT ANY CONTACT.