Is it safe to eat expired eggs?

A friend of mine has been using eggs that have a sell-by date of June 8 and when I pointed this out to her a few weeks ago (I assumed she hadn’t noticed they’d expired) she said they were fine, that she’s eaten expired eggs before and never got sick. It’s July 24 now and the eggs are still being used. Growing up my parents never kept expired eggs, so I don’t have any experience with this. I myself haven’t been using the eggs, but I’m concerned for my friend as well as curious as to what’s the worst that could happen from consuming these eggs. What’s your take on this?