The 19year-old was charged with abuse or neglect of a child causing serious emotional or physical injury – a felony punishable by up to 15 years in jail.
The baby’s mother, 20-year-old Megan Hendricks faces the same charge as police say she witnessed the horrific abuse and didn’t get help, the St Louis Post-Dispatch reports.
Baby Jax, who is now in protective custody, is being treated at Cardinal Glennon Children’s Hospital.
His condition was described as critical on Thursday.
But police have been told by doctors that it’s ‘likely’ the boy will die and if he survives, there is a high chance he will be extremely physically and mentally disabled, the Post-Dispatch reports.