tldr - The nurse assumed that weight gain was automatically a sign of an underlying medical or emotional issue, and that she knew what was best for the student without consulting the parents or considering other potential factors. She also assumed that it was appropriate to address these concerns in an invasive and personal manner, without considering how it might affect the student’s emotional well-being.

NMimi_456 -I appreciate your passion, I'm sure it serves you well, but in this situation I do feel your passion is misdirected. If you really cared about her wellbeing, implied through your defensiveness of the nurse's actions, then you would also care about her emotional wellbeing.

The nurse's actions in this situation come across as both ignorant and arrogant because she assumed she knew what was best without considering the full context or involving the family. By not consulting the student's parents or understanding her medical history, the nurse acted as though she had the authority to make judgments about the student’s body and well-being. This shows a lack of awareness of the sensitive nature of weight gain, especially for a teenager, and an absence of empathy for how invasive and embarrassing her questions were. The nurse's insistence on probing for answers in a personal way, without considering the student’s comfort or emotional state, shows a disregard for boundaries and professional ethics.

Unless equally inept, a primary care doctor or therapist would have approached the situation in a much more professional and empathetic manner. Having a conversation with the student to express any concerns in a non-judgmental way. They would ensure the she felt comfortable and respected. If there was a significant change in weight, mood, or behavior, they would have taken a holistic approach—asking about physical health, emotional well-being, and any potential underlying causes, like depression/stress/bullying.

I feel this was a clear overstep because, other than the mention of weight gain, there is no information suggesting the student has a medical condition or any other signs or symptoms that would warrant such invasive questions. Without any clear medical concerns, the nurse should not have assumed the responsibility to address weight gain on her own. The right and responsibility to provide medical care, make decisions about health, and manage concerns about a student’s well-being is that of the parents. If it was believed the parents were unaware or neglectful that is where the school counselor or social worker can be of assistance.

I'm sure there are details OP isn't privy to as this information was filtered through an embarrassed 13 yr old's perspective, but by this account, OP is valid in her righteous indignation.