One of DD's best friends at school (aged 7) has parents whose marriage appears to be on the rocks. I don't know the mum well - it's more of a hi/bye thing at drop off and pick up - but bumped into her on the street the other day. She randomly burst into tears and made all sorts of serious allegations against her husband, none of them I want to repeat here because they could be outing her/me. The allegations are all to do with the dad's behaviour against the mum, not DD's friend. The woman seems to be in a bad way and on the verge of a breakdown.
I don't know the family well enough to know if she is telling the truth or to speak to the dad for his side of the story (nor do I want to). The best friend seems happy and cheerful whenever I see her at drop off / pick up time - but obviously I do have a concern about whether the child in question would be picking up on the aforementioned issues at home, should the allegations be real.
AIBU to ignore this? Or should I speak to someone at school (e.g. safeguarding contact, even though at this point the concern is for the school mum rather than the children).
Edited to add - I was sworn to secrecy by the mum. She doesn't want to take it up with anyone.