He sadly does act on incest thoughts but stops mid-way bc he's brother is telling him to stop. When he was vulnerable the brother took advantage of that. The doctor does end up confessing about how he has this worry of him leaving him and regretting every saying things like "I want to get married" or like regret loving him. He was t honest about his feelings(which was pathetic).

I reached the side story and I cannot continue at all. Can someone let me know if it gets better (honestly there is NO redemption for the doctor), and PLEASE tell me the brother doesn't act on his incest thoughts. I really liked the first couple, but I will not be continuing if it does happen to be pure incest. That is a red-flag for me, completely.