B. Each public institution of higher education shall provide a refund of the tuition and mandatory fees paid by any veteran student for any course from which such veteran student is forced to withdraw, for the first time, due to a service-connected medical condition during a semester, as certified in writing to the institution by a physician licensed to practice medicine pursuant to Chapter 29 (§ 54.1-2900 et seq.) of Title 54.1 who treated the veteran student for such medical condition. Such refund shall not be issued when three-quarters of a course has been completed at the time that the veteran student withdraws from the course. The time period that constitutes three-quarters of a course shall be determined by the institution.