Could sleep apnea go away without treatment?

Not usually: There are different causes of sleep apnea. Some may have anatomical reasons such as large tonsils, a narrow airway or a deviated nasal septum. Obesity can also cause sleep apnea. There is no guarantee that with weight loss that the disorder will go away. Without treatment, sleep apnea can cause other problems such as high blood pressure or heart problems.

Sleep apnea: Probably not. Unless someone is very overweight and loses all the extra weight. Otherwise, there can be several causes to sleep apnea from obstructive ( air compromised, large tongue, adenoids, tonsils etc) to central (brain dysfunction). In any case, the lack of oxygen during sleep can lead to heart attack, diabetes, stroke etc. Without treatment you are shortening your life.