I'd consider approaching the operators of Nana Plaza and offering the domain name to them. They have deep pockets and I imagine they'd be interested, even if only to tie up the domain name so someone else couldn't acquire it. In terms of the big picture, I don't think it's a domain name that will have value forever so if it were me, I'd consider selling it.
Sorry to hear the news, but nobody lives forever 😞
He was a great source of entertainment in the 1990's and a bit after.
We are all diminished by his passing.