I do remember, however that J1 didn't really want a slave but sort of just went along with it and ignored J2 as much as he could - even giving him his own room upstairs and telling him to do whatever.
I also remember that J2 had a somewhat abusive owner previously and don't believe the room was actually meant for him, so he sleeps in the (ancient) "traditional" slaves quarters in the damp cold basement. The showe down there didn't have any hot water and J2 was too afraid to eat J1's food - so instead he just ate some kind of dog food-esque mix that was supposed to be supplemented to slaves or something.
The last bit that I remember was that all that stress combined with the malnourishment and exhaustion caused J2 to fall off a ladder and end up in some janky slave hospital?
I may be mixing up fics... Hopefully that helps! If anyone has any ideas or similar fics, thank you in advance!
*The fic was Flightless Bird by foolsdance