Standalone PC need to get LiveUpdate definitions

How can I update an Unmanaged Client without Internet in an environment where there is a only 1 machine ( say X) that is connected to the internet and communicates with SEPM. The other clients are just standalone PC's which communicates with only X. So how can this unmanaged client communicate and collect information from it?

Please tell me the steps to do it. Its very Urgent

This CLIENT PC is a standalone machine.

1)not connected to the network but only communicates with X (parent PC).

2) no internet enabled

So how can we get the  virus updates/definitions updated on this CLIENt automatically