Ds left school in the summer and has been messaging on instagram an ex teacher of his. He is 17 and she must be mid 20s. I know this because he left his phone home while going out one day and messages came up, I know it's bad but recognised her name and read them. Started off innocent about how he was getting on now but have turned quite flirtatious. Obviously I am massively concerned about this. AIBU to message the school saying this young teacher is flirting with my DS who has only just left school months ago? Or is it none of my business now he has left, and perfectly legal? Really not sure of rules on this!