Odd that this wasn't mentioned yesterday! That isn't odd. They have a duty of care to him too. It is odd that they have now told your DW this. That would also cover the discrepancy of the sexual/non sexual touching comment, neither of which should have been said.
The HT should have said very little to you. Whilst I appreciate that your care and anger is for your DD the HT has an equal duty of care for the confidentiality and safety of both children. She has now broken that confidentiality and may need retraining, herself.
I know you don't have to care, I wouldn't give him a second thought if he did that to my daughter, but what if you were a less well adjusted individual and started to tell all your friends, the other parents what he HT has said? What might the repercussions be?
The HT has been very unprofessional. In worst case scenario, she would have contaminated / biased a possible witness statement. That is something that is very, very carefully underlined in all safeguarding courses, even more so for named person training.
I hope your DD is OK, and I hope you and your DW are coping with the whole thing. But, honestly, the HT has done noone much good here and, ideally, someone will tell her so!