Responses

It's like this. Jaewon (MC) hate drugs, because they made him lose control (and let's be honest, his life IS shitty enough without him losing control).
The Brown haired guy knew that he hated pills, and he knew what buttons to push só the MC would use them either way. He gave the pills and instructions to the Black haired Guy, so the Brown one could swip in and sabe the day, saying that he would provide for the MC, etc
I don't understand the scene with the pills. Was the black hair getting pills from the brown haired guy so he can drug jaewon?