Medicine & Retakes of AS

(On behalf of my boyfriend). He got a D in Chemistry AS today and in applying for medicine will need BBB at A-Level at the lowest. Universities say for medicine they like you to get your A-Levels on the first attempt... If he were to resit his Chemistry AS exams next year as well as doing the Chemistry A2 exams would this be OK? He won't be applying for uni until after he has his final results either because he's taking a gap year, so technically they wouldn't know...