That's an additional complication as far as resetting the hub and reconnecting your wi-fi devices. You will probably need to find out more info from your son before resetting the hub.
The wifi from your hub works on two frequencies at the same time (2.4GHz and 5GHz). When you are trying to connect to your wifi network you look for your hub wi-fi name which will typically look like VM1234567.
By default (and after a reset) the 2.4GHz signal and the 5GHz signal both use exactly the same name so to find your wifi network you look for VM1234567 (your own network name is the SSID name from the hub sticker) and you tell your device to connect to that.
Some devices, however, are only capable of using the 2.4GHz frequency band and can be difficult to connect when the two frequency bands use exactly the same name.
To get around this, it is possible to give each frequency band its own name (which allows the 2.4GHz devices to find, and connect to, the network). This can be changed via the settings for the hub.
So, when the wifi on the hub has been split in that way, your hub may then show two separate wifi names such as
VM1234567_2 and VM1234567_5
for the 2.4GHz and 5GHz bands separately.
Depending on what devices you are connecting to your wifi network, this might actually be a good/necessary thing to do in order to allow particular devices a reliable connection.
It sounds like your son has split the wifi bands.
If you reset the hub, it will revert back to the single name (e.g. VM1234567) and your devices may not recognise that single name and may no longer connect. You may have to re-enter the wifi details again for the single wifi name or you may have to re-enter the split names/password back into the hub which should then allow your devices to reconnect again without reconfiguring them.
I think you will have to involve your son in this to find out more about what he has done and why he has done it.
Who set up the hub and the wi-fi devices in the first place? Was it your son acting in an 'authorised' capacity when he did so?
Personally I would recommend doing any changes to the hub through a login via a web browser. The VM Connect app is probably more trouble than it is worth.