How dreadfully unprofessional.
After applying for a (non-aviation) position some years ago the same thing happened, a "yeah but nah but yeah but nah but..." series of phone calls worthy of Little Britain, with a lot of added guff about quota numbers / being able to get a position on the next intake /sorry we dicked you around etc etc etc. After a week of daffing around involving about five phone calls I really didn't care if I got the job or not... and after being offered a position (finally
)the inital stuff-around had a big impact on my future loyalty. After five years of employment I never quite forgot the initial debacle, and had no hesitation in leaving for Something Better the moment it came up...though I did refrain from giving the boss a Character Assessment in case the same thing happened again!!
Of course mistakes happen, but HR types should be mindful of the massive impact a phone call (either positive or negative) will have on the prospective employee and take appropriate care. From personal experience, there is nothing worse than proudly announcing to friends and family that the coveted job has been won, only to have to issue a retraction. Even if it turns out positively (as it did for me), the debacle takes most of the shine off the victory, and makes you feel like an also-ran.
The Titanic and the Exxon Valdez were also terrible mistakes. This does not make either exusable.
Best of luck to your friend, karma works in mysterious ways and it may all work out for the best!!
WIW