They both used Yahoo Mail and for some reason best known to himself he normally used his wife's account for sending and receiving mail, consequently all his emails, contacts etc are in his late wife's account.
We got round the emails problem by forwarding the latest and most relevant to himself and that seemed to work. We also sent a group email to all his contacts asking them to use his own email address from now on.
However we have come to a standstill over the contacts. We were able to export them from the late wife's account as vCards to a USB stick and then import them to the desktop in my friends account, but we could not find a way to persuade Yahoo Mail to import the vCards.
Eventually as his friends and relatives reply to his address change email he will be able to add them to his contacts, but it would have been neater to be able to copy the contact across.