Coaches take promotions and demotions all the time and Kyle worked under Kubiak in Texas for 3 yrs before joining his father in Washington.
While that is true, the dynamic in this case is pretty unusual:
-Shanahan worked for Kubiak 4 years ago in a higher position
-Shanahan is a finalist for this OC position only to have Kubiak swoop in a the last second to take the job
-To take a job with the Ravens, Shanahan would have to take a demotion and effectively be in the same spot he started in 8 years ago.
Don't get me wrong, is love for it to happen, and with no other OC positions, it might, just don't know how happy he'd be about it. Also, don't know if the fact that Kubes has known Shanahan since he's been in diapers would help or hurt lol.