Good for you trying! Maybe next time try sleeping at Horseshoe Meadows one night and then at Whitney Portal the next. First night camping out is always tough for me -- I take benadryl to help me sleep on that first night.
It looks like he stay two night at a Mammoth hotel. I would think he'd get much better sleep there at 8000+ feet than at Horseshoe Meadows. IMO unless you can sleep well two nights before the hike, it's not worth the acclimation effort.
