Sounds like a major 'gerd attack' - I used to get them all the time - where i'd wake up choking and coughing, and my lungs would feel as if they were dipped in napalm.
If it IS GERD, he'll have to get treated for it before it causes trouble with his lungs (like pulmonary fibrosis, etc.). Also...he might have sleep apnea - has he ever been tested for it? That's where you wake up multiple times during the night (usually unaware) and stop breathing for periods of time. A sleep study can determine this, and there is treatment. I have it, and use BiPAP. There's a chance that between my smoking (I quit in 2003), GERD, sleep apnea, radiation to my right chest for breast cancer in 2001, and unknown causes (autoimmune is speculated), I have Idiopathic Pulmonary Fibrosis (IPF)...it was diagnosed as COPD in 2005, but it might have masqueraded as COPD. My latest PFT's showed a major drop from last year to this year (from 77% function to 34% function) and those with COPD usually don't lose that much that quickly; and a major shift to restrictive disease rather than obstructive. An HRCT and echocardiogram were done last week. Hopefully, the HRCT will be enough to diagnose it without having to do a lung biopsy. - but it looks like IPF. CT's of abdomen incidentally show scarring at the base of the lungs, and fibrosis is scarring.
Hope this is of interest/help.
God Bless
Gina-MI