OP says the kid has been "all over scratch" so we can assume they need something more

It's another Chromium/Electron based app, so it may not be suitable for low end systems, but still, it's weird that it doesn't load at all. I don't know how to help, sorry.

I find it pretty inefficient to start up a Python environment, a web server and a web browser to do something that you could do with Notepad or even in a terminal. I would use Notepad++, gedit, Kate, vim, vscodium... There are plugins for vscodium (and vscode obviously) to preview Markdown if that's what you need