An appeal trial at the HCMC People's Court on Wednesday accepted the prosecutors' appeal and the defendant's counter-appeal, dismissing the father's lawsuit.
The verdict from the first-instance court was amended to allow the mother to continue to have direct custody and care of the 7-year-old boy. The father is allowed to visit the child "without obstruction" but must not disrupt the child's schooling.
The court said the first-instance court's conclusion that the defendant, the ex-wife, "is no longer able to directly look after and care for the child because she has a new family and a new child" was "subjective."
In reality the child is happy whenever he plays with his younger sibling, and the boy also expressed a desire to live with his mother, it said.
The boy was seated separately from his parents, and so the father's claim that he was "influenced by the mother" is "baseless," it said.
"A child's development requires not only material needs but also emotional stability and peace without mental disruption.
"Parents need to jointly care for and bring up a child to not adversely affect it; they need to be calm and considerate and prioritize the child's interests," it said.
The court also noted that the father's action of recording a video of the boy saying "I want to live with daddy" during a visit could affect his psychology.
"Although the mother has a new family, she does everything needed to raise the child. The first-instance judgment to hand over custody to the father could disrupt the child's psychology and life."
Seven years ago, returning after studying abroad, the couple met through a matchmaker.
They eventually married and had a son.
But conflicts began between them, and they decided to divorce when their son was around six months old.
In August 2017 a court in HCMC's Binh Thanh District granted them divorce by mutual consent.
They agreed to let the mother take care of the child, with the father visiting on weekends. The mother did not ask for child support.
In July last year the father filed a suit requesting a change in custodial rights, arguing that he had agreed to give custody to his ex-wife during the divorce because the child was young and now wanted custody since he is older.
He said she had remarried a foreigner and had a child with him, and so was not providing enough care for his son, affecting his mental health.
Besides, she had enrolled him in an international school that uses French, and could not read or write Vietnamese though he was about to enter second grade.
He also said the child showed signs of malnutrition and was physically and mentally underdeveloped compared to his peers.
Raising him in a foreign culture was inappropriate and contrary to Vietnamese customs, he claimed.
At the time of divorce they had agreed he would only visit the child on Sunday mornings because he was an infant, but even after he grew up his ex-wife limited his visits to Sunday mornings, which was inappropriate, he said.
Even these visits were affected because she often took the child on long trips, he said.
At the trial the woman rejected his demand saying she could provide good care for the boy, and changing the caregiver would disrupt his life, which is currently "happy and stable."
She also said she did not restrict his visits, and he even took the boy for weekend outings and visits to his parents' house.
The boy attended an international school and could communicate in French, English and Vietnamese, she said.
A medical examination at a hospital showed the boy was healthy and developing normally for his age, and so the father's claim he was malnourished and mentally and physically underdeveloped was incorrect, she said.
Her current husband, an educated foreigner, was a good husband and father to both children, and the boy lived in a proper family with love from parents, siblings and grandparents, she said.
But the court did not accept her arguments and ruled in favor of the plaintiff, granting him custody of the child.
The woman then appealed to the Tan Binh District Court.
The district procuracy, the prosecutor's office, argued that the court should overturn the earlier verdict.
Its representatives pleaded that the mother should continue to have custody of the boy considering his comprehensive interests.
The father's claim that the child could not read and write Vietnamese and objections to his cultural milieu are baseless, the prosecutors said.
They pointed out that the father has never taken care of the boy and lacks child care skills.
The boy is accustomed to living in his mother's care, and abruptly changing his living environment, teachers, friends, and educational methods would pose difficulties for him, they warned.
So only allowing the mother to continue to raise him would safeguard his interests, they added.