If I make a comment, the recipient will be advised.
But if he has not read it and I delete it, will he still be advised and able to read it after my deletion?
Georges, this just happened. I left a comment at a question; the OP edited the question and left me a comment to take a look. Maybe 15 minutes later he deleted the entire post. However, I was notified of the comment.
From your wording, you are asking about when someone deletes a specific comment, not an entire post. Oh, well. In this case, everything will still be in place for viewing. Note that, in The Intern with Robert de Niro, a turning point occurs when they go to the home of Anne Hathaway's mother to delete an email/text/whatever mistakenly sent to the mother's computer.