Recovery from unusual attitudes is required during primary training and must be demonstrated during the checkride. In the case of an incapacitated or disoriented pilot, will activating a single-axis autopilot in ROL mode while in an unusual attitude safely recover straight-and-level flight?
Generally, no. There's always an exception out there someplace, but I've never seen an autopilot that is advertised as being able to recover from an unusual attitude situation. Depending on exactly what the attitude is, the mode of the autopilot, and its specific capabilities & mechanical limitations, you MIGHT be able to get out of an unusual attitude that way, but I wouldn't count on it. And it's certainly never taught that way anywhere that I've been... you're taught to recognize-confirm-recover by flying out of the unusual attitude yourself, rather than relying on the automation to do it for you. (In fact, if you get into an unusual attitude, chances are decent that either mismanagement of or a failure in the automation contributed to getting you there!)
Given the wide range of possibly unusual attitudes & aggravating circumstances (i.e. engine out, rudder out-of-trim, shifting or shearing winds, structural damage, failed pitot/static instruments, failed gyro, etc etc), I'd be very surprised if any manufacturer would ever claim that their autopilot could be relied upon for this task.