I couldn't make a comment on facebook, but you should copyright this and then report his page on patreon. He's saying it is a free mod and can do whatever. I tried reporting the page. I am glad I could bring it to your attention though.
It's unfortunate but there are a lot of scrubs out there that do the same thing. They're technically not wrong to say they can do what they want with them as once they are released, there's no way to stop people from editing them. They do in fact become public domain and copyright can't be challenged. Truth be told, the original author likely did a lesser version of the same thing because it's highly likely that he or she didn't get permission from Freightliner to make the mod in the first place. While that's not an "apples to apples" comparison, I just mean to say that the whole process is born of hijacking. I think modders like this guy who charge for something that they for all intents and purposes, "stole" is deplorable. Especially given that the guy who did all the hard work, gave the thing away for free. That Withersoul idiot went so far as to require his own store category mod AND payment for nothing more than EXTREMELY poor conversion of someone else's hard work. I blame home schooling and libtards.