The U.S. Department of Transportation does not necessarily issue restrictions on sleep apnea. However, the Federal Motor Carrier Safety Administration has sleep apnea regulations for drivers, and the Federal Aviation Administration has sleep apnea regulations for pilots. The FMCSA and the FAA are both agencies of the DOT.
There is no rule that directly restricts someone with sleep apnea from operating a motor vehicle for private or commercial use. However, commercial drivers are not supposed to drive if they have conditions that could pose a danger while driving. If the sleep apnea is properly treated, the driver may return to commercial driving service.
Sleep apnea is a heavily controlled and monitored condition. Current experience of sleep apnea would medically disqualify a person from being able to serve as a pilot for private or commercial applications. The pilot may be able to get a special issuance once his condition has been properly treated.