Also, tell them to be suspicious of email links that require them to log in. If "PayPal" sends an email saying you need to change your password or log in for some other reason, teach them to go to type paypal.com in the browser themselves instead of clicking the link.
Absolutely, repeat this a bunch of times even at the risk of being a bit annoying. It's worth it. Make that point. Anyone asking for your password or other sensitive info is very likely a fisher (aka a thief).