in another day long before the Vytalfestival was held Ozpin and his Inner circle found out that Leonardo Lionheart, the Headmaster of Haven academy, had betrayed him to become Information for Salem because It's implied that Lionheart betrayed Ozpin's cause due to learning about Salem's immortality and only started helping him during the two years and finally Leonardo was arrested and after that Qrow was appointed Headmaster of Haven Academy. At first Qrow refused but there was no other choice. Qrow became Headmaster of Haven Academy and protected the Relic of Knowledge. Even after the Fall of Beacon and Ozpin's death, Qrow remained Headmaster, he knew about what's going on about Ruby and Yang's situation because they always text Qrow

Qrow : sigh while taking a sip from his flask I'm bored while reading some documents that he hates to read