I hope it’s fine if I post a picture of a manga I’m reading here:
Chapter 6, Chainsaw man 1
The boy lost his pet (it died) and it became his heart.
The phrase she says in the bottom there is tripping me up.
I think it means:
«As for him living in there, its useless comfort»
I suspect it’s だの (and~) grammar but I know that なんだ is a different thing by itself. What is going on here?