Agreed
But tbh he can't really run from him since the guy is rich, is a gangster, and knows where that guy in the beginning works. I think the author is portrayed the later chapters a little worse that she did in some of them
I don't know about him being a closeted masochist, but I don't think we are supposed to feel sorry for him. There is still so much we don't know, but I feel like once the uke stops crying while he gets abused, that will be the turning point in this story. The title can be translated to "An Easy Target" which makes me think the only way this can end well is if he truly stands up for himself and ends up with no one. There are also a lot of BL that doesn't have the rape/Stockholm Syndrome trope, you just have to search for it.
I would say I'm sorry for him...but I'm not. I'm really not. He's basically a closeted masochist. And I hate all the siblings except the girl. She SEEMS less messed up, though I wouldn't be surprised if she turns out just as messed up as the other 2. I really thought this would be different. I thought he'd be tough and beat the crap out of that phsychotic THING but no, he "sacrificed" himself. This is just like most of the other yaoi mangas I've read. Isn't there a mangaka out there who DOESN'T think that rape and Stockholm Syndrome is makes for a captivating yaoi story? It's really noticeable that atleast 68 % of yaoi mangas or stories have rape, masochism, sadism, Stockholm syndrome, betrayal, manipulation etc. in them and about 60 % of of the readers buy into the little moments that the capture acts stupid and cute.