Authorities say Lakendra Nicholson appeared to be intoxicated during the time of the crash when she struck several cars.
The boy died in his mother's arms at the scene, his family told ABC13.
He was in the backseat of a vehicle that Nicholson is accused of hitting.
Witnesses described seeing a speeding driver and hearing "terrible noises," before they realized a child was in the vehicle.
"All of a sudden I heard a big crash and I ran over to the street and saw this car had run in behind the ladies in the black car. The other lady hit another car. Immediately we tried to help the people who was in the car," witness Paul Johnson said.
Investigators say they recovered white pills in a Crown Royal bag and a "smoked joint" from inside Nicholson's wrecked vehicle.
When authorities made contact with Nicholson at Memorial Herman Hospital, they said her eyes were bloodshot red, her speech was slurred and she appeared disoriented.
Officers said Nicholson couldn't recall much leading up to the crash, but she did remember having two Bud Light margaritas.
Reports stated that Nicholson pulled out her left breast during the sobriety test, and refused to provide a blood sample.
Nicholson is charged with one count of intoxication manslaughter, two counts of intoxication assault and one count of driving while intoxicated.
Court records show she was previously charged with DWI on March 13.
She is being held on a $70,000 bond.