Every three hours for the past three weeks, she expresses milk into a cup to be fed to baby Sibusiso via a tube, even though every minute might be his last.
Doctors say there is nothing they can do for him.
His condition is officially “incompatible with life”.
Sibusiso was born on July 4 with anencephaly, a birth defect that results in a brain growing outside a head.
According to his paediatrician, Dr Lizzy Tabane, the condition occurs early in the pregnancy at about four weeks after fertilisation, when the brain is still being formed. As the baby develops, the skull does not close properly and leaves a hole at the back of the child’s head.
Most of the brain grows outside the head and is covered by a very thin membrane.
Infants with anencephaly usually have a brain stem, which controls reflexes like breathing, but they do not have a forebrain or cerebrum that controls thinking.
“The brain that was formed is abnormal. The brain consists of the cerebral hemispheres on the sides, the cerebellum at the back as well as the brain stem. He has no cerebrum or cerebral hemisphere, just brain tissue and a brain stem which is connected to the spinal cord and helps him to breathe.
“But unfortunately he won’t last long and there is nothing we can do about it. There is no quality of life without a brain. All that we can do is offer him palliative care as there is nothing curative about his case,” Tabane said.
But despite being told that her first child might die at any time, Mokoena was praying for a miracle.
While she understands the seriousness of her baby’s condition, she says she is “waiting for him to get better. I have hope that he will be fine.
“I am so scared of lifting him up in case I hurt him. That part at the back containing his brain is very soft, it’s like touching a plastic with water. So I’m scared I will tear it.”
Mokoena’s partner, Sandile Sithole, has refused to accept that there was nothing that could be done for his baby boy and was searching for assistance.
Mokoena said: “He is hurting. This is his first child and it is difficult for him to accept what happened.”
Tabane said they had already counselled the couple and told them that they must “let nature take its course”.
In the meantime, she said, all they were doing was keeping the baby comfortable.
In her 17 years of being a doctor, Tabane said, Sibusiso was the third case of anencephaly she had seen.
The first child, she said, had died after a week and the second one after four weeks.
According to the US Centre for Disease Control and Prevention, the prognosis for patients is death.
Most anencephalic foetuses do not survive birth, and account for 55 percent of non-aborted cases. If the infant is not stillborn, then he or she will usually die within a few hours or days after birth from cardio-respiratory arrest.
There have been three recorded cases of children who have lived longer. Stephanie Keene, of Virginia, US, lived for two years and 174 days, and Nicholas Coke, of Pueblo, Colorado, is still alive after three and a half years, and Vitoria de Cristo, born in January 2010, is also still alive.
Anencephaly occurs in about four out of 10 000 births. Having one infant with this condition increases the risk of having another child with neural tube defects.