Living off the grid with a laptop [closed]

I’m a seal, please don’t eat me, I really don’t know anything about computers. I’m asking for my son, who is and has been living off the grid for a few years. None of this makes any sense to me, but it will to him. This off-grid laptop is now not functional, and he needs to replace it with a used laptop with software that can currently be obtained and activated.
Once I can get the details on current software limitations, I will have the laptop and any needed software shipped to a local computer shop (local to him) with the exact instructions of what to install, how to install it, and what options to include, from him. They will prepare the computer and activate everything which will be the last it will see of the internet. He will then collect it.
He tells me the best experts are on StackExchange and someone there will know how this can be done. Although the answer will require some software recommendation, it’s really not just about that, but the limitations in the current world of subscriptions and software as a service. With his previous computer he was able to do with Windows and MS Office, but I know that might not be an option anymore. He would also sometimes use (OpenSUSE).
He needs the computer to be able to function for five plus years without any internet connection or any ability to “call home” to keep a license alive. It is a single computer solution, so no special multi-user licenses or other things like that are usable. It must be all “off the shelf up” options. He needs to be able to create and edit all of his documents, (all existing in MS XML format); print to create, annotate, edit, split, and merge PDFs;play MP3 and MP4 files; and do some form of 3D modeling. It must also have text-to-speech and editing support for three different languages, for instance, English, Greek, and French. He’s confident that he has the answers for all of those questions except for the OS, Office Suite, and PDF tools. That’s why I’m asking about those here.

Direct questions.

  • Can this still be done with Microsoft software?
  • Can this be done with OpenSUSE and LibreOffice?
  • Is there a PDF editor that can work fully offline?

PS: Feel free to DM me if you would like to offer help that way.