Central sleep apnea, if it is a problem, can only be treated via what is called an adaptive servo-ventilator (ASV). His insurance may require him to try to be titrated successfully with a 'bipap' machine, but I can almost bet it won't work. They want to keep their costs down because an ASV, which must be replaced every five years as a regular PAP machine would, and where they're on the hook for a good chunk of the cost, is twice as costly as a regular PAP machine.