groovy girl. Could you google the electoral roll for Oxford to find his mother's address. You could write saying you are an old friend who would love to get in touch with her son. If he's alive, well and good. If not I don't think his mother would take offence. On the other hand you could try the Registrar for Births, Deaths, and Marriages in Oxford, and enquire if they have a record of your friend's death, as if he has sadly died then it is likely that the death would have been registered in his home town, by his family. At least it would give you closure. Good luck with your search.