Thanks buffy and soursprout - he is fine thank goodness and now he has a phone he can use we have returned to something approaching normal service 
I agree about not offering advice asking about revision. Although I did say to him just now that he needed to get back in the swing of things, revision-wise, and he agreed and admitted that he has not done enough maths over Easter, which is definitely one of his weakest subjects. I am a little worried that he's resting on his laurels for English, History, Geography and to a certain extent Spanish, and not worrying about the others too much because he thinks knows he'll get 5 really solid marks there. I've not said this to him though...
But hey ho...what will be will be. I must admit that I feel much more philosophical about it all than I did a few months ago. He'll be ok, he's not going to crash and burn, he's a bright, happy and personable young man with a loving family and lots of friends and exams aren't everything!
But he will be spending all Saturday at school in a geography revision day 