I'm only a decade younger - I write .Net (C#) professionally - work it is Windows & Visual Studio (there is no way I'd want to mange any project that size without an IDE, tbh I much prefer using a IDE since I first got one in early 90s)
But at home - I use Jet Brains Rider (free non commercial) for C# .Net projects on Linux machines (Debian + KDE or Mint depending on machine)
I wonder if you mean Notepad++ not Notepad - I find KATE on KDE is good enough, when I just want to edit a file, but I've run Notepad++ under wine before.
I didn't think TextPad was included in Windows as it not a Microsoft product or free.
If you mean WordPad, which was on Windows - that is a simple Word Processor , so not suitable for writing code in.
Not sure how he will get along with all the stuff MS is adding to I'd suggest getting to look at NotePad++. On Linux Mint Xed behaves similar to Notepad
A super basic text editor is available anywhere. He's comfortable with many of them when editing other things (like vim/nano/ed on Linux)
He just likes Notepad for his personal use. Now that you mention it I do believe he used Notepad++ at some point (only 3rd party editor he's tried). I don't remember at what point he dropped it but he didn't use it long.
Like you said, with Windows 11 replacing Notepad with a rewritten version, he's probably going to have to switch to Notepad++.
I was hoping he'd just switch to Linux. Even tried baiting him by giving a pre Linux installed fully configured laptop with a beautiful OLED panel and great keyboard. He loved the hardware and reinstalled Windows.
But at home - I use Jet Brains Rider (free non commercial) for C# .Net projects on Linux machines (Debian + KDE or Mint depending on machine)
I wonder if you mean Notepad++ not Notepad - I find KATE on KDE is good enough, when I just want to edit a file, but I've run Notepad++ under wine before.