So how do I get credit for inviting a friend to play Warlight?

( It's worth like 3500 points. )

And is it too late, ( I started a year ago), to help the friend who invited me,
to get the proper credit?

https://www.warlight.net/invitationnetwork

I mean, there is no way to "invite" a current account. So, yeah you can't help the friend who invited you :(