Hi, what you ideally need is NoMachine Anywhere which is in its final stages of development. This will be perfect for users who either don’t know their IP or are not able to configure their router for whatever reason.
On another note: you don’t need any of the Enterprise products to remotely connect, the free NoMachine package that you can download lets you connect to your remote computer (your uncle’s in your case). Check the tutorial here (fig 8) https://www.nomachine.com/getting-started-with-nomachine#internet
If you have already and no IP and port number is showing up, it could be your (uncle’s) router doesn’t support UPnP. Or that our UPnP doesn’t support your router . Anyway this shouldn’t affect your ability to connect, even from the outside. Many routers that don’t support the query for the external IP still accept the commands required to enable port forwarding. If not, it then becomes necessary to configure port forwarding by using the router admin interface which is precisely what you are not able to do.
NoMachine Anywhere will alleviate all of this.