lung cancer post op

[cpufem]

my dad's over a year out from lung cancer surgery where he had multiple lobes of his lung removed. the other day he was complaining that he was beginning to inhale his food. literally. he had inhaled a small chunk of lettuce somehow while he was eating and had a horrible time coughing it up later. i urged him to email his nurse from the hospital which is treating him but something tells me he won't.

how serious of a concern is this?