thanks for your question I completely understand your problem firstly chest congestion means there is an infection in your husbands chest which is leading to increase secretions causing congestion. this all increased secretions can be due to an infection building up in the chest. if sputum is yellow then he has to take a course of antibiotics after consulting your physician. secondly if your husband is not able to expectorate the phlegm then you have to assist him by physiotherapy and postural therapies.you can consult a pulmonologist who can examine . i don t think cpap has much to do with your problem thanks/regards feel free to ask more questions may god bless your family a good health