Lisa98

It's been so long since I saw ULS so I don't remember it well, but it doesn't surprise me since Hotae's mother did so much for Donghee, he really is like a son to her. Me too I want to see how they get past all this miscommunication and finally be together. I really hope there will be a sequel about their lives after ULS.

From what I saw in the serie/movie Hotae stopped calling Donghee "hyung" because of the double interpretation, I think. "Hyung" meaning a big brother (being related) and also a mark of respect to an older guy (for boys). It feels like since they were really close since childhood, already living together and even their moms defined them as brothers at the begining, Hotae didn't want people to misunderstand them as brothers (being related). That's why from the time he stopped calling him "hyung" he couldn't go back to it. I think it's a big part of him acknowledging his feelings for Donhee, at least a part of them. But Donghee didn't know that, he was just living his life as usual and suddenly Hotae changed his way of interacting with him. It's more difficult for me to understand Donghee's feelings about the "Hyung" thing but my guess is that the first time he asked for it he had mixed feelings between being called "hyung" becoming something special between them (since Hotae didn't use it anymore) and being an escape, thinking that Hotae wouldn't say it and the situation they were in would be over. The second time he asked for it, I think this time it was to put some distance between them. They had already been through so much together, going back to being called "hyung" was like going back in time before anything happened. It really felt like he was asking Hotae to forget everythig and go back the way they've always been. But Hotae couldn't do that, it was too important for him so it wasn't a surprise that he refused calling him "hyung". Donghee reaction to his answer felt like he was accepting that everything had already changed, like he had a little moment of hope and asked, because he was probably too afraid of the reality, but he already knew he had no other choices than to accept the reality and that's what he did by accepting Hotae answer and changing the subject of the conversation.
That was my answer to the "hyung" thing, I hope my interpretation can help.

About Donghee fighting his feelings, maybe you're right I hadn't thought of that I had a totally different interpretation while watching.
For me Hotae was the character who had internalized homophobia while Donghee was true to his feelings. Hotae since the begining acted like he was in love with Donghee but he kept doing stuff that put them apart like having multiple girlfriends, he didn't say a single thing at the hospital when before the accident he was running to him, etc. But at the same time he was very honnest with his affection for Donghee, that could've been interpreted as friend's love if we didn't know about his acts (sneaking, looking, wanting to kiss, ...) as outsiders. But Donghee didn't know everything that we saw as viewers of the drama, so I think for him Hotae was like a little brother, who dated girl (even if he didn't seem very interested in his relationships) and who was confused about him (meaning confused about Donghee). So Donghee could easily misinterpret the situation by thinking he was the cause of Hotae's confusion, same as his love wich created confusion in Hotae's mind and since he thought for Hotae instead of asking Hotae directly what was on his mind (communication is really the key), he thought that he was ruining their relationship with his love so the only way to make Hotae happy again and make his confusion end was to stop loving him (in a romantic way) and to do that he had to leave. I don't think the mother was taken into consideration in his choice of leaving, it felt like he only thought about saving their reltionship, not that it could hurt Hotae and Hotae's mom relationship, but you could be right. Maybe he was also afraid of that, even if we, as viewers, could see that the mom clearly knows something, maybe she didn't get thet extent of their love but she knows they love each other a lot. In my opinion Donghee really didn't understand how much Hotae loved him (in a romantic way), maybe he thought there was at least some kind of attraction, but I don't think he understood more than that. It felt like he thought Hotae only viewed him as a best friend and Donghee was the only one with these kind of feelings so it didn't felt right to him to like impose his feelings on their relationship. If only he knew...

We clearly need a sequel showing what happened after Unintentionnal love story !!