Representatives from Carolinas Medical Center report Kathy Eller died Thursday.
She was taken the hospital earlier this week in critical condition.
Police say Eller's 17-year-old son, Austin Hunsucker attacked her at their Granite Falls home Sunday.
One of Eller's neighbors heard screams coming from the home, but didn't think anything was wrong at the time.
Police say Hunsucker used several instruments during the attack, including a golf club, a glass cross and a glass pot lid.
He was originally charged with Assault with a Deadly Weapon with Intent to Kill Inflicting Serious Injury.
Police have not said if he will face more serious charges now that his mother has died.