Theoretically, if your Dad gets the Boss Katana and becomes proficient on using the USB computer connection to get his amp settings and effects from that, there really would be no need to get pedals, especially if you are not thrilled with the idea of spending $$$s on pedals.

The Boss Katana is a highly respected amp and there are a ton of YT videos out there about using a Katana in a general sense and also for specific tones. Here's a couple for you:
https://www.youtube.com/watch?v=mq6nxN6nWvg

https://www.youtube.com/watch?v=kSXi0wZA47c