It would be the rare exception for students at these schools to take a semester off for an internship. Internships are done in the summer. Students who attend these schools overwhelmingly graduate in four years.
In any event, students have to reapply for need-based aid every year. In general, there are no guaranteed multi-year need-based grants (exceptions for QuestBridge and similar programs), so there’s no FA to “lose” if he is not enrolled for a semester. (Although I supposed there could be limitations on some named-donor grants.) You can expect that the FA will be the same or similar if your circumstances remain the same or similar. OTOH, if he is actually enrolled for more than eight semesters because of academic difficulty, you’d have to ask the FA office what the stipulations are for institutional need-based aid being given beyond 8 semesters.
How much aid did the NPC say you’d get at these schools? If you are eligible for a Pell grant, the max is 12 semesters. For federal subsidized student loans, it’s 150% of the duration of the program (so, six years for a typical bachelor’s degree). But, again, if he’s not enrolled, that semester does not count.
I don’t believe there is a limit to the number of years for an unsubsidized loan.