Reverse x0tigervnc application

[psilospiral]

I have an older family member now running Debian who needs occasional on-screen assistance from remote.  This machine is behind a router without the possibility of configuring port forwarding, UPnP, etc. and can occasionally move to a different AP for internet connectivity, such as a hotspot on a mobile phone.

I run a proxmox server at home behind a pfsense router with a dynamic DNS address that I can fully configure.  

My thought is to configure a VM on my proxmox hypervisor to listen for connection attempts from the remote family member's Debian machine.  Then configure the remote family member's Debian machine via a script to make continuous connection attempts to my VM via a script file fired every so often by crontab.  I would then either launch vnc on the VM and/or open the port to accept the connection when they need assistance.

How can I configure tigervnc on a VM on my hypervisor to display my family member's x0vncserver connection in reverse (so that I can see the family member's screen on the VM instead of them seeing my VM screen) ???

[DRC]

You could accomplish that using the UltraVNC Repeater, but only with a
VNC server that supports reverse connections.  That unfortunately
doesn't include x0vncserver.