At MIT, motivated kids can wrap up their undergrad in 5-6 semesters (which requires a few AP credits - MIT doesn’t take very many, testing out of intro classes, and taking moderate extra load during the semesters), and either move on for a right opportunity or stay for a fully-funded Masters (Masters funding is department-specific).
Since cost is a concern, this is something to consider if their kid is a likely candidate for early graduation.