Sad to hear but I actually think KDE like Gnome should build their own distro. Everything else is always going to be a little half arsed or out of date. They seem to do it for Plasma Active, which could work out.
A similar approach should work for KDE. Just pick one base distro (which has to be community controlled) and build KDE SC ontop. (Debian, Mageia or Gentoo could be good bases to build on)
About Kubuntu, it would be sad to see it go, but I am actually way more sad to hear that Jonathan had an accident.