He's using a password manager (Keepass, in his case) probably with a long, randomly generated password for Reddit. This is a great cybersecurity practice.
Last count, i have well over 300 online accounts - and i don't know the password for a single one of them, except for my main Google account and my password manager. It remembers all of them for me.
24 random letter upper and lower case, numbers and special characters. that is more than enough to stop brute force cracking. unless someones nuts and uses a server farm