Andrew Loyd was being treated at Le Bonheur Children's Hospital in Memphis after the shooting, which was reported to the Alcorn County Sheriff's Department late Monday night. He was flown to Le Bonheur where he has been reported in critical condition since that time, said Chief Investigator Tommy Hopkins.
The Alcorn County coroner was notified that Andrew Loyd died at 2:30 p.m. Thursday.
Andrew Loyd was found wounded in an apartment at Farmington Arms, along with the body of his 51-year-old father, Billy Loyd, Hopkins said.
Authorities went to the apartment near midnight Tuesday after a caller reported seeing a disturbing message on Billy Loyd's Facebook page.
According to the Facebook friend, Billy Loyd had posted information about financial problems and the fear that he would be evicted and his son taken from him.
Billy Loyd also left funeral instructions for both himself and his son and asked anyone who read the post to call the sheriff's department.