Stop Snoring Remedies

i heard my dad make a whistling noise while he was breathing at night, first it was normal, then around every 10 seconds i would hear a little whistle. i saw the lung cancer commercial about hearing a whistling noise. my dad smoked since he was 12 and now he is 40. he had a checkup for lung cancer in february and nothing was found. the whistling noise also wasnt very loud, it was kind of faint.