I'm not sure what your question is but since the loan originated prior to his active duty date he is entitled to the 6% rate limitation.
(a) RESERVES ORDERED TO REPORT FOR MILITARY SERVICE- A member of a reserve component who is ordered to report for military service is entitled to the rights and protections of this subchapter and subchapters II and III during the period beginning on the date of the member’s receipt of the order and ending on the date on which the member reports for military service (or, if the order is revoked before the member so reports, or the date on which the order is revoked).
Based on the definition for a Covered Borrower I don't believe the MLA was applicable at the time the loan was made.
(6)(A) The term “active Guard and Reserve duty” means active duty performed by a member of a reserve component of the Army, Navy, Air Force, or Marine Corps, or full-time National Guard duty performed by a member of the National Guard pursuant to an order to full-time National Guard duty, for a period of 180 consecutive days or more for the purpose of organizing, administering, recruiting, instructing, or training the reserve components.
The opinions expressed are mine and they are not to be taken as legal advice.