The father is merely trying to teach his daughter a valuable life lesson about responsibility and the consequences of one's actions. While it's natural for a parent to want to shield their child, sometimes the most loving thing to do is to allow them to learn from their mistakes. The school's rules are clear, and the daughter knowingly violated them.
This father's self-righteous stance is a thinly veiled attempt to avoid conflict with the school and appear morally superior. He's sacrificing his daughter's future prospects for the sake of his own image. A good parent would exhaust all options to help their child, even if it means bending the rules a little. His refusal is nothing short of parental negligence!
The daughter knowingly violated the school's rules by bringing her phone to the restroom and potentially using it to cheat. The father's refusal to intervene is justified, as enabling her would only reinforce a lack of accountability. While the ex-spouse's frustration is understandable, shielding the daughter from the consequences of her actions would be a disservice in the long run.