Son seen girlfriends mother kick her

[SecretMe]

This is exactly the same as a woman (or man) being in an abusive relationship. Only this time it's a 16 yo girl, still a child in the eyes of the law. Nothing excuses the mother's behaviour, can you chat to the GF and explain that it's not ok and she shouldn't have to put up with that. She asked your DS to forget about it, that's a real sign that this is happening regularly.

If she has another relative to stay with that'd be great, is there a Dad on the scene? Like you, I'd have to do something, Tusla, Gardai, is there a phone line that could help, Childline maybe? At least you'd be getting proper advice.