Personally liked the fact it was acknowledged as a possibility, chalked it down to anxiety from mc even if kaoru was bi, bro js needed the reassurance of kaoru only liking him, tho i do understand where ur coming from
Biphobia is blatant in yaoi, but in the particular manga I kind of understood what the actual issue was. The only guy that Toma dated was a complete asshole and told Toma he was essentially “alone” for those 10 years when he was still happily sleeping with women. Toma’s fear makes sense, but it’s not like he thought anything negative. It was more of a “oh I don’t actually know about this thing” thought. Kaoru’s reaction is a bit more on the line, but even so it felt more like he was drawing the line for Toma while expressing his unhappiness.
The grandpa is so nice he’s the best character! I don’t like the subtle biphobia though, feel like they glossed over that..