This is what the more recent studies have found. He can of course eat things like mas potatoes and buttermilk . You did realize the first list were foods for him to avoid, then the second listing is of foods that are recommended. This is medical information - what is now recommended by the medical community.
I can send you information that I have written up before on acid refux. As far as sleep apnea, I'll send you a good resource on this, I don't know if there are meds that help for this. Usually it takes either C Pap breathing machinery, loss of weight, or surgery.
I'll start with information on dealing with gastric reflux.
There are a lot of measures to treat the symptoms of this problem. These includes certain regimens of H2 blocker and other medications such as pantoprazole and rantidine. For permanent resolution of this problem, it may help to understand that weight is a big factor in causing this, so calorie reduction and increasing exercise are overall goals that should be sought.
As you note, there seems to be increased problems when you are laying on your back. Often people begin to notice it after laying down, because lack of gravity will now allow more of the gastric juice to get up into the esophagus and pharynx. To prevent this from occurring as much it is recommended to sleep with the head of your bed up. It is best to do this by placing a wedge between the mattresses or by getting a hospital bed or other type of bed where the head of the bed can be rolled up. Besides sleeping and napping with the head of the bed up, sleeping on your left side will help to keep the gastric acids from getting up into the esophagus. This reflux of the acids into the esophagus is what is causing the excess saliva and mucus - the gastric juices, which normally are retained in the stomach in order to digest the food in your stomach, are basically "digesting" the skin or tissue lining the esophagus. The gastric fluids can get all the way up to the larnx. This of course is damaging and can lead to more problems such as chronic coughing, hoarse voice and even strictures in the esophagus. The body reacts to this by making excess saliva and mucus in an attempt to "wash" away this irritating fluid.
Besides obesity as a factor in keeping the esophageal opening to the stomach from closing properly, other factors are genetic propensity, types of foods you eat (spicey or acidic are more irritating), and eating too much in one sitting contribute to the problem.
Again, you will need to see your doctor for definative diagnosis and mediations. But I do have more information on things that will help you. A lot of people have this problem, so I have put this together in the past. Excuse me if some of it is repetitive.
This is a list of things that will help resolve the problem:
If you smoke, stop.
Avoid foods and beverages that worsen symptoms (acidic foods - tomato, fruits; carbonated drinks; spicey foods; onion)
Lose weight if needed. Exercise and eating the right types of food, in my opinion is the best way to lose weight. Cut your portions a bit at each meal. Try walking 30 minutes per day. Work up to 60 minutes per day if your doctor approves. You may divide it up into smaller amounts - 10 minutes here, 20 minutes there, etc. A pedometer can also help you keep track of the amount you walk during the day and encourage you to take that extra step you need here and there to increase the amount you exercise.
Eat small, frequent meals. It is usually suggested to eat 5 meals a day, but smaller. This increases your metabolism and will help with weight lose. It takes energy (calories) each time you digest food. Speeding up your metabolism causes you to use more calories all day.
Wear loose-fitting clothes.
Avoid lying down for 2 to 3 hours after a meal and don't eat for 2 to 3 hours before lying down at night.
Raise the head of your bed 6 to 8 inches using extra pillows or purchasing a wedge to place between the mattresses. Of course a bed where you could elevate the head of the bed would be ideal. If you are not comfortable laying on your back with the head of your bed up, then try laying on your left side. This keeps the contents of the stomach in your stomach.
More rest and sleep if you are short on these.
This link goes into much more detail about this problem, in case you are interested: http://digestive.niddk.nih.gov/ddiseases/pubs/gerd/
Besides those things, this article also lists interventions as well as some clear advice on food to avoid, and foods that are okay. These things are what most people find very helpful:
Recipes ideas to prevent acidity, give you an idea of foods that will help you.:
FOR THE SLEEP APNEA - here is a link to articles from the Mayo Clinic. They discuss all the treatments for sleep apnea, depending on whether he as central or obstructive sleep apnea: http://www.mayoclinic.com/health/SEARCH/Search
I hope this added information will help. I know it is a lot of info - but I assure you this is some of the best and most up to date information on these disorders.