Building around (or inside) existing buildings is sometimes done to work around strict building codes or @$$hole clerks that have it in for you and won't approve your renovation plans. I have seen it a few times. :-)

Strange, not nearly what I'd call nightmarish.

Alright, when can we expect the before and after story ?
I need to know about this DIY project and how much money and time he spent.

A sh#tty remodelled half rotten house full of trash. Remind me why this would be even mildly interesting.

I would say, tear the thing down and rebuild. Why would you want to re model something that’s completely rotted.