Rick has discovered that people are logging into his Facebook account without his knowledge or consent. Leo says he should change his password immediately and turn on 2-factor authentication. It will prevent another computer from logging into his account, even if they have the password. Facebook also stores a cookie in the browser that will enable him to open Facebook without logging in. So he shouldn't use Facebook on a public computer.
Doctor Mom says that Facebook will let you use a one time password if you text "OTP" to Facebook. They'll send you a one time password. He can use that for when he's in a public area.