This phase II trial tests the effect of decreasing (tapering) doses of dexamethasone on steroid side effects in patients after surgery to remove (craniotomy) a brain tumor. Steroids are the gold standard post-surgery treatment to reduce swelling (edema) at the surgical site to reduce neurological symptoms. Although, corticosteroids reduce edema, they have side effects including high blood sugar, high blood pressure, and can impair wound healing. Dexamethasone is in a class of medications called corticosteroids. It is used to reduce inflammation and lower the body's immune response. It also works to treat other conditions by reducing swelling and redness. Tapering doses dexamethasone may decrease steroid side effects without increasing the risk of edema in patients with brain tumors after a craniotomy.