It works fine for me with a 64 character password. Maybe the server errored out randomly that time. What browser are you using?

If you shoot me an email with your username, I'll delete your account and files manually.

How will you know the person emailing you is actually the owner of that username?

I'd send an email to the email address they signed up with to confirm.

I wouldn't call that minor. Sounds like there's something odd about the way passwords are handled. :/

He probably uses a password manager and generates them randomly. Nothing odd about that.