You mean he quit his job without having another one already lined up.
Boy, was that ever a bad move.
The situation was of such nature, that he left on a spur of the moment, although he hadn't been planning on quitting. It was an ongoing conflict with total lack of communication, he was working overtime but being paid less for that than his regular hourly wage, and expected to work every weekend although it wasn't his regular schedule. When he confronted his boss about the overtime pay, she said "well, it's better than nothing".
One morning when he went to work and saw that more work had already been piled up, he just left... with no notice.
He tried calling her, but she doesn't answer the phone, and doesn't return messages.