Indeed. What I know, guys who put out his tracks on compilations already c. 15 years ago, had no means to get replies from him. Pretty much everything stops in late 90's. Only few obscure collaborations that probably were made by other participant. For years, once in a while, I have tried to google, search social media, and find the person but no luck. If someone from Japan knows what happened to him, information would be greatly appreciated.
His old tapes reissued properly on CD would be highly important. Good quality LP probably fine, but original artwork would be best to format into CD size.