Is the wireguard tunnel set up on their router? I like this idea but my parents have a router provided by their ISP and those routers don't often have the ability to do such things.
My family uses linux so every pc has their own wireguard endpoint.
Also in my personal network I got multiple routers and one of them is connected to wireguard as well
I assume it's from their machines to some machine controlled by OP. Probably not a home router.