Thank you all! I really appreciate it (so does DH).
He was sent another email last night by the deputy head that seems to be gunning for him (there are three deputy heads!). Tone was very unfriendly.
However he managed to get hold of NEU last night - thanks Piggy for the suggestion. They were very supportive, gave him advice to follow now to go off sick with stress and DO NOT resign even if he isn't sure what he wants to do long-term. He has got a GP's appointment in about 30 minutes. They will get a local rep to contact him within 5 days.
The NASUWT rep is a really good sort and has been trying to advise him unofficially but obviously as they are different unions he can't actually do anything,
He had taken printed copies of all the emails he has received and sent and noted down times and dates of other events.
The complaints ranged from petty to semi-serious. Petty - he wears a hat in school sometimes and used his phone on school premises - more serious - not providing information to other members of staff (how vague can you get?) Anyway the point was that he was not informed of the nature of the meeting was before he turned up and all the complaints were anonymous so they refused to give him details which made it very difficult to argue with them. And there were about 17 issues so it was as if they just got everything anyone had ever said about him (one issue seemed to have been from the year before as far as DH could work out) and dumped it all on him at once.
The other factor in all this is that he tore his anterior cruciate ligament whilst carrying out a restraint on a 15 year old last summer. it is serious and has been told by one consultant it is inoperable although he is getting a second opinion. He is constant pain and has to wear a knee brace most of the time - the school does not have enough staff who are willing (or trained?) to get involved when some of the bigger kids kick off and he is often one of the only ones who does. Hence more than one injury over the years but this is the most serious. He can't cycle, he can't walk very far, he is putting on weight and is thoroughly fed up. I think he should make something of this personally but it's up to him.
But he is at home for now, having a much needed rest.
We're away on Saturday for a wedding - just us, no kids - so it will be a break and a change of scene.
thanks again