Why would you even consider the possibility that he should sell his house, considering the aforementioned halacha that he should be supported to live at his original standard of living?
I would guess because he can no longer afford to keep it and if he doesn’t the bank will foreclose on it.
Personally I’m not rich but I do OK. I had a rough patch last year and a few people helped us out. I kind of felt really bad about it because even with all that was going on I was pretty sure I was still making more than one of them. Mostly we got a lot of moral support, which really did help up keep going.