If the other person has a Tailscale account, it sounds like the most expedient method is to simply invite them to the tailnet as a non-admin user with strict access control.
You could share a node with an outside user, but I don’t know how much the quarantine would affect its functionality. You could also use Funnel to expose the node to the internet (essentially like a reverse proxy), but there are obvious vital security considerations with that approach.









It’s problematic, but possible: https://jamesguthrie.ch/blog/multi-tailnet-unlocking-access-to-multiple-tailscale-networks/