(a) There are medicines which are affected by light. The compound in the medicine undergo chemical reaction and get converted to other compounds in the presence of light. As a result, the medicines are no longer effective. So in order to prevent such kind of reactions, they are stored in dark bottles so that light can't enter the bottle.
(b) Similarly, some medicines are sensitive to heat. When the temperature is increased they undergo chemical reaction and lose their properties. So to prevent that, some medicines need refrigeration.
(c) I am not sure which value, but i think he fulfilled the duty of a responsible citizen by reporting the matter to the medical superintendent.