Kevin is looking for a password vault or manager to store all his passwords. Leo says that the best password is long and strong, with random characters, letters, and punctuation symbols. But he'll never remember it. That's why Leo recommends LastPass, which can not only generate the passwords, but also can keep them safe. 1Password is another. This also creates a single point of failure, though. There's nothing wrong with having a notebook that he can write them down in.
Vaults take a bit of getting used to, but once Kevin is, it'll be the best possible system for remembering and protecting his accounts. All he'll need to remember is one password to access his vault.