I am not into Yaio manga but this one manga actually has a story. It starts out with a regular guy. I think his parents are already dead so the person looking after him is an older sister like figure. I think she was his brothers wife but I don't remember if he was alive but she does have a son. One unfortunate day when he was away criminals barged in their house and brutally raped and killed her in front of her son's eyes and that was when he just came home and in shock and anger he brutally murdered all the thugs which her son also happen to see. Her son became mentally disturbed after the incident and with no one to defend him he was arrested for quite a few years. In jail her was raped repeatedly. He was not released until the day his sister like figure's relative showed up to help him. This man I think was her older brother. After he was released he started living with this man and trying to get his life back on track. He also started to have relations with this man. Her son is now in a mental ward and constantly has mental break downs when he tries to see him after such a long time as her son is the only family he has left.

I think it's Hana to Ryuu

Thanks thats the one. I wonder why no group finished it yet especially the ones into yaio manga. It only has a few more chapters left and unlike the others it has a very interesting story.