From Wikipedia: “The barber surgeon, one of the most common European medical practitioners of the Middle Ages, was generally charged with caring for soldiers during and after battle. In this era, surgery was seldom conducted by physicians, but instead by barbers, who, possessing razors and coordination indispensable to their trade, were called upon for numerous tasks ranging from cutting hair to amputating limbs.”
A self-taught medic fits better the Griffin theme of being a race without a real culture or self-respect outside thir extreme greed and gruff behaviour. Gyrp is more of a weird guy with a morbid curiosity, an interest in anatomy and an insane sense of humor, yet he tries his best to keep the party alive or at least all patched up and ready to fight.
“Oops, zat was not Medicine!”