If they’re only in for the money, then they’re going to get run over very quickly unless if they’re a very determined person that wants to go into management/business with an engineering degree.
If they have a strong interest in an area that relates to engineering, and they’re willing to take on the challenges and accept setbacks (many engineering student had that one test or project, or a course where they struggled), then they’ll do fine in engineering.
I had Bs and Cs in high school math courses, and AP Calc crushed me. Yet I went into engineering anyways, and I’m currently working at an internship that I enjoy.
I skipped a lot of parties and other sorts of distractions in order to focus on studying, engineering student organizations and career networking.
EDIT: There was also an Uni of Penn research that proved there was a direct correlation between mathematical skills and ability to concentrate.