First red flag was when the mmc graciously decided to wait for the fmc to turn 18 before pursuing her. Second red flag was when he found a photo of them together when he was 18 and she was 13 (!!!!!!!!) and reminisced fondly on the love in his eyes for her, even then. Super predatory behavior and absolutely inexcusable, especially given that the author explicitly states that she has gone back and made other socially conscious adjustments to the original story. I get that brother’s best friend is a popular trope but I found no reason for the age gap to be so large or the behavior so predatory.