Charles might have been ready for a sympathetic ear from one of Diana's "friends", no matter what the age? Apparently she was going to Highgrove a lot..............but I don't remember where I saw that. Here's something I just found today that tends to suggest they did have some kind of friendship at one time:
>>British royal Prince Charles has refused to invite Sarah Ferguson, Duchess of York to his wedding to Camilla Parker Bowles - following their vicious row at a royal dinner in 1999.
The heir to the throne and Ferguson allegedly parted on bad terms following a mystery argument at the prince's Highgrove home.......<<
Prince Charles Refuses Wedding Invite to Sarah Ferguson - People