Yes, Sabren was formerly Cornerhost's business name, and it's still where hosting takes place. Cornerhost basically = Sabren.com. My servers for all my (very many) domains are all at ns1.sabren.com and ns2.sabren.com.
I was able to FTP in and get my stuff. Others on the mailing list that's been set up have not been able to. I don't know why. But clearly some people have already been locked out.
After I wrote this today, I discovered a person who seems to be a relative, who I reached out to, and that person said they would pass along my information to the person who runs the hosting. So, apparently he is not dead. But I still am wagering that he's had some sort of very big problem.