When any trainee has an unexpired benefit year for disability benefits at the time of induction into the armed forces, the unexpended balance of disability benefits remaining to his account shall be reestablished beginning with the first day of the first week succeeding the date of his termination of service. The balance shall be paid at a weekly rate in accordance with Section 2655. In the event the records relating to the unexpended balance have been destroyed under proper approval, the trainee may establish the unexpended balance by affidavit as provided by authorized regulation. Whenever this balance is exhausted the trainee may file a claim and his disability base period shall be determined in accordance with Sections 2770 and 2610 or Section 2611. All reestablished balances shall lapse 65 weeks after termination of military service.