Set up family library sharing remotely?

[venomtail]

Forgot to set up my family sharing on a laptop. Is there a way for me to set up family sharing remotely? I know the other steam account that should have access. Can I send the authentication to said account? Can I manually set the computer id for family sharing?

Don't want to do a 3h trip one way just to log into my account to press one check box of "authorise library..."

a really big misuse of my time. Hope there's an alternative

[Spawn of Totoro]

If they are family and you trust them, you can give them the log-in information over the phone along with the authenticator number from the Steam authenticator. Then they can authorize Steam Family Share. (This isn't recommended as it does pose a security risk.)

Otherwise you will have to do it in-person.

Forgot about this, so I'll add it:

They can also allow remote access to their system, though that still has some security risk involved, but it is another option.

[[N]ebsun]

Use something like teamviewer or remote desktop, then disable / remove it after