Emergency services were called to an address in Wallsend, North Tyneside, at 2.15pm last Wednesday and found a 21-year-old woman and her three-week-old son with life-threatening injuries.
The woman is now said to be in a stable condition, but Northumbria Police confirmed on Monday that the baby had died.
Detective Chief Inspector Dave Cole, of Northumbria Police, said: "This is a devastating time for the baby's family. Specialist officers continue to offer them support and I know the community in Wallsend are by their side too.
Man to appear in court
"It is impossible to imagine what they are going through and I would ask the public to continue to respect the family's privacy at this time.
Beytula, of Portland Close, Wallsend, appeared at North Tyneside Magistrates' Court on Thursday, where he was remanded into custody.
He is now due to appear at Newcastle Crown Court on October 31.