It was asked by someone else but it's interesting, hopefully someone knows about it.
So this uke, the BL Manga I'm looking for, is homeless. When it gets too cold at night, an old homeless man brought him a warm sandwich and talks about how they probably wouldn’t survive if the weather got even colder. He told the young boy to go back home but the uke starts having flashbacks so I guess he was probably being abused or neglected at home and maybe suffering from childhood trauma. When it gets colder, he remembered the old man telling him about the huge mansion nearby that was almost always abandoned. Nobody has seen the owner ever going in or out and only the servants responsible for cleaning occasionally show up..He gathered the courage and sneaked in. First he went into the attic which was locked from outside and somehow managed to go to the kitchen and ate a whole bunch of food lol. Little did he know, the refrigerator was filled up cause the owner was about to show up on that day. It's the Seme. He even hired a male sex worker to enjoy his time there. Uke was in the attic, directly above the seme's bedroom. At one point, seme starts having sex with the male sex worker and uke peeps through the crack. It seemed like seme knew he was being watched but kept going.
Seme had a tall muscular body and dark hair. The uke was competitively weaker (physically) and shorter. I don't exactly remember the color of uke's hair but he did wear a cap at one point, a pair of worn out jeans and jackets. Seme was wearing a long coat on his first appearance on the panel.