The American Red Cross doesn't collect autologous donations at a regular blood drive. Autologous donations are collected separately & usually before a planned procedure. This episode implies that person donates their own blood & it's held until needed. Whole Blood is good for only 6 weeks after collection. AB+ blood is also the universal recipient, meaning can receive other non-identical types.
The hospital is supposed to be in Cabot Cove Maine (or close). However, the hospital says "Medical Centrer, Dalesboro, Ohio