Mikiharu

I read this around 2014~15 before mangago went error a lot.
Warning: R***, Inces*, un-alive attempt, un-alive
How I remember the story,
they are brother (doesn't remember if it's blood/step)
the younger one start as B-complex turn yandare
He kidnapped, imprisoned, and rape the brother.
Big bro managed escape couples time, one time with friend help but always got caught again.
Big bro also tried overdose but failed.

Ending:
Big bro manage to win his trust and he got allowed to go to river alone. He went too long so lil bro look for him. To find him lying by the river and over dose. So he followed him(? I think)