I have Steam, and there is a WW group on there. Not used often, except for Arma3 for me. Oh, and IL2 Bob (the one in between 46 and Stalingrad.)
I would recommend he buy and install IL2 BoX (or DCS, P3D, XPlane, etc) outside of steam. He can still add it to his Steam game collection and even launch it through Steam.
But buying and installing it through Steam means he's limited to whatever updates, etc, 777 has made for the Steam version of IL2 BoX.
That said, Steam and its communities can be very useful. Especially if a group has no other means of getting together (no website of their own, for example.) Steam also costs money, and is a commercial venue funded through sales. Expect ads throughout the Steam universe.
Compared to other gaming community apps out there, Steam is by far the largest. But there are alternatives. I'm posting this via mobile, so don't have access to some of the others I have (a free game from my video card meant I had to install a Steam-like alternative, that has since changed its name.)
A screen cap of the mobile Steam app's chat box, showing currently online friends...