Self sufficient EEA national but child British

just a quick question

If an EEA national is exercising treaty right as a Self sufficient normally he/she need to have comprehensive sickness insurance for everyone in the family but what if her child is a British passport holder ? Child is British because her ex partner was PR holder but she is not

I don't think child need to have CSI too like her MUM who is still an EEA national

No Need for the British Child to have CSI , I believe