Realistically, I think the OP’s family may weigh both GPA and the difficulty of the school when deciding on future funding. At least the case should be made for this, as excessive strictness may only discourage the OP from reaching his potential.
Beyond that, I think the OP should be offered some sense of what a typical college GPA may be. At Harvard, it is 3.67, for example. It can’t hurt to know that, even if at an engineering-intensive school it may be less.