vitamin pills vs. vitamin injections

He is getting injections because his stomach was removed. Humans cannot make B12 in the body, rather they have to absorb it from the food they eat. Small amounts of B12 are absorbed in the mouth, but the vast majority is absorbed later. In the stomach, the food we eat is digested, and a chemical called intrinsic factor is released. As the food passes into the duodenum (first part of the small intestine) the B12 that was digested from the food, is processed and combines with the intrinsic factor molecules, and then is absorbed in the ileum (last part of the small intestine) and put into circulation.

Anyone who has their ileum or stomach removed ends up requiring B12 injections, since without them you cannot absorb enough B12 to maintain bodily functions.

He needs it because his stomach was removed