How should this teacher be dealt with?

[Babbaganush]

Have change some details so not identifying.

Dc came home from school upset that DHT had confiscated an item of hers and from a few other classmates. Pupils arrived at class to find teacher not there, message comes through to go to hall where teacher was doing something. Class sit around while teacher gets on with what they are doing. A pupil askes if they can do something that is a direct breech of school rules, teacher agrees as long as he is not disturbed. Towards the end of the lesson DHT walks in and confiscates items from pupils near the door (those who had seen him approach hid items before he could see) Class teacher allows DHT to give pupils seen breaking the rules a telling off.
My dc is a stickler for the rules and was mortified to have been told off for something they had been allowed to do by teacher. I emailed school and explained dc version of events, head investigated and confirmed dc version was correct and that teacher was very much in the wrong, did not have permission to be where he was and should have been teaching class.
As far as I was concerned the matter was closed. Dc had this teacher this week and they went on a rant to the whole class and singled out dc mentioning my email!!! Dc was very upset, was seen by the HT after the lesson who enquired what was wrong. I have emailed the school with my concerns and the HT has been great, agrees teacher should not have raised the issue.
It is now in schools hands, my question is what action would you expect to be taken? Secondary school dc is Y7.

I can picture the dht sweeping into the room, spotting the phone users and effecting an immediate confiscation. Teacher flustered and keeps quiet. Should absolutely not then have a go at the students.

DC has this teacher again today - first time since the teacher ranted at the class and singled dc out, I'm hoping that the lesson passes without incident!

I've said all along that I am happy for the head to deal with this, I don't understand why people keep responding that I shouldn't expect to be updated about what happens. The circumstances of the initial incident have been investigated and it has been accepted that dc version of events was correct, the class were not in their timetabled classroom but in another part of the school where this teacher was doing something with a group of other pupils without the knowledge of SLT, some of the other group were already using their phones, dc class were instructed to sit down and keep out of the way, pupils asked to use their phones as the others were using theirs.

Hope your DC has an uneventful lesson today OP. My DC has only ever been told off twice, both times by the same teacher, for what DC sees as things they didn't explain/unfair etc. I'm always on slight tenterhooks on Geography days now!