In my career as an airline pilot I have seen so many attempts by jilted pilot girlfriends, usually flight attendants, who did all kinds of things to try to get him fired. Alcoholism, drugs and instability led the list.
If her report on his text is all they have he will probably clear himself in due time. Drunk texting should not be used as evidence in court or most of us would be in trouble. She dumped him was the report but things get twisted when emotions run high.
Hopefully he isn't as represented so he can get his life back.