@Daniel ****
, if you lack an understanding of how the legal system works, you should refrain from commenting. It is disrespectful, especially considering the seriousness of the situation.
I outlined the specific Thai laws governing this matter, provided links to legal resources in Thailand, and detailed six scenarios illustrating what could go wrong.
Tldr:
The wife can file a baseless petition and have the father & childs passport seized while a court case is pending.
If the Thai court has not been properly informed, they retain the right to:
1.) Protect their own Thai national, "the child."
2.) Review the information & ensure that, from their perspective, the child’s best interests are fully considered.
One argument could be that the family’s current instability due to the child being separated from the mother necessitates prioritising the child’s stability, which may involve remaining with the mother.
Scroll up if you would like to read my full detailed explanation and analysis.