Fair points 1261.
I suppose the question is did he act reasonably at all times and to the best of his ability. The answer has to be no, but at the same time he was not negligent in my view.
He did make mistakes, but understandable mistakes, and he is only human after all.
Re: the telephones - he could, and should, have told them to get lost, but he was trying to cooperate and would have felt he was being unhelpful not to.
The real error was his failure to call his colleague back when things got busy. But again, he was I suppose only trying to be cooperative with those around him. He was not being negligent in my opinion. It's easy with the benefit of hindsight to point out where he went wrong, and when he took those decisions he could have had no idea of their ramifications. Stating the obvious I know, but it's worth bearing in mind that this was just another quiet evening and he would not have been anticipating any of the circumstances that contrived to cause this terrible accident.
I do feel the utmost sympathy for him, I suspect many good controllers would have acted as he did and if just one chink in the armour had remained disaster would have been averted. Like almost all aviation accidents. He will have to live with this for the rest of his life, and with the knowledge that he was just unlucky for this to occur while he was on duty, and incredibly unlucky in that if things had been just a little different (ie the Boeing had been 20ft higher) it would have gone down as just a very dangerous airprox.
One lesson that I think should not be forgotten from this accident is that the Captain should always call the shots whoever is on the flight deck. The apparent argument between him and the more senior check Captain was crucial to the accident, the Captain of the TU knew he was being checked and could not have felt good about contradicting a direct command from a senior pilot. But his reaction to follow the TCAS RA was the correct one. The Captain's decision should never be compromised. Even if all around him think it's the wrong decision - and even if it is the wrong decision.