Does Teamviewer depend on the Net to know one's Your ID?

My brother just called and for, I think, the first time, I couldn't fix
him up, wrt Windows.

When he started teamviewer, the box for "Your ID" was blank.

(When I started mine, it was blank for a second and then filled in with
my usual numbers.)

Later he found the icon for Gmail and it said he wasn't connected to the
internet. Could that be the reason Your ID was blank in TeamViewer.

I thought that the Teamviewer Your ID was inside my computer, but maybe
they send it to me each time I start TViewer. Any guesses????

I thought maybe the whole internet was down for him but he tried to get
on two days ago too, with the same problems

--
His printer wasn't working (again) and he called some Geek who actually
came out, but now the E for Edge is missing from the bottom of his
screen; when he searched for Edge and found it, something else went
wrong; and the TeamViewer Your ID is blank. Does it sound like the
Geek messed something up, maybe?