I saw your comment that you're in a iOS/macOS office. If you get stuck, macOS has a built-in WiFi scanner that displays the optimal 2.4 and 5ghz channels for a device's location. This might quickly help improve some areas and here is an explanation of what it does.

https://www.imore.com/how-use-macos-wireless-diagnostics-get-best-possible-wifi-settings-your-area

Pass. If this goes sideways, it will be beyond the "friend's" relative's ability to fix it and you have the most to lose.