Quite apart from the dreadful errors leading this stuff being out there on there in public, the more I think about it, why were staff sharing correspondence like that with their Trustees anyway?
What decision, or support, or to what end was this sharing this personal info with the Trustees in the first place?
Trustees aren’t staff, they don’t carry out the work of the charity, Trustees set the direction for the staff and have responsibility for the charity’s work to be fulfilling its legal aims.
Did the parents know this sharing would be happening and give permission for their correspondence with the charity staff to be shared with Trustees?