Just shut up please, you don't see Doom going at Halo for having similar things. Also, if this is unity, it'll probably look the exact same, so please just mellow out. I don't know much about code or anything like that, but one dive into the code is probably better than immediately going after someone.
Yes, I get your point. The code within the game probably is done differently than Scrap Mechanic's code, but it has the same game features that are unique to Scrap Mechanic.
Listen, if this game is a learning experience for him in terms of coding, good for him. This game has probably taught him many of the basics in Unity, but if it is just a test or learning experience, say so, and don't try to sell it as an original game.