Jefferson is a nurse in a hospital. Alex has hemophilia (he's really embarrassed by it cuz he hates constantly being asked if he's okay) and frequently gets in fights so he's at the hospital a lot
Hemophilia is a rare disorder in which your blood doesn't clot normally because it lacks sufficient blood-clotting proteins (clotting factors). If you have hemophilia, you may bleed for a longer time after an injury than you would if your blood clotted normally.