Go to setting , click Network and Internet, click ethernet, click network 2 or whatsoever your network name is, then turn on the Metered Connection 
You will now avoid to install windows update automatically... hope it helps..
You will now avoid to install windows update automatically... hope it helps..That will only work if his/her pc is on wifi connection. I know there's a trick to make your ethernet connection as a metered connection. Here's one.
https://www.cnet.com/how-to/meter-your-ethernet-connection-in-windows-10/
If you need more assistance I can help you on this.