correct but there are some rules. for example if he owns the company 49% he can be only in position of adviser or marketing. plus company must sell abroad. also farang cannot help any work such as making furniture and sell. he can do the selling part but cannot do the making part. if a foreigner do a work it means thai national not qualified for the position so the company needs a foreigner. Also street selling is 100% forbidden to farangs. also making a hamburger dont need a foreigner cook.
so most likely hes doing this illegal and im so surprised no IMM checked him. he even has tiktok. and he sells ramkhankeng area near the university.
i dont know maybe he has some kind of permit or maybe hes thai citizen.