Thank you everyone, I found what I was looking for & now the computer can see the phone.
Steps taken:
1. I opened Settings>System>Developer Options>Default USB Configuration.
2. I then selected File Transfer. That's what we needed.
As for this being in the swipe-down Notification Panel, I see no way to place it there.
I opened Settings>System>Developer Options>Quick Settings Developer Tiles, but there is no selection. I only see:
Show Layout Bounds, Profile HWUI Rendering, Force RTL Layout Direction, Sensors Off,
Window Animation Scale, Winscope Trace, Wireless Debugging & Show Taps
But he doesn't need it in the Notification Panel anyway.
It does show up as its own device in Windows Explorer, which is what we needed.