My usual advice is to bring Diamox if you think you might need it, but only take it if you develop symptoms. I only suggest taking it before symptoms develop if you have a history of altitude problems. This is a case where I think taking Diamox could help. Sleep apnea on top of Cheyne-Stokes breathing wouldn't be nice.
I prefer to camp as high as possible, but I would recommend camping lower if it won't put the summit out of reach. Doing it in a day would get around the sleep apnea at altitude issue, but that may not be an option.