Pure speculation is that he along with a lot of other folks got caught up above treeline on Saturday. Plenty of folks are willing to take the risk for nasty weather on summer weekends. Even the forecasters qualify their forecasts and say "no need to cancel activities, just keep an eye out for thunderstorms" I was in Milan on Saturday and although there were plenty of rumbles from 12:30 on, the actual storms didn't arrive until 2 PM.
It can take quite awhile to get below treeline in some spots on Crawford Path. Even the patches of scrub between Eisenhower and Pierce are really not adequate for true cover from a hard strike. I expect that it wasn't direct strike but rather a strike in the vicinity that got him. Individuals can get impacted for quite a radius around a strike. Recommendations I have read for hiking out west in groups is to maintain 1/4 mile between hikers if possible so if one get hit the others can respond. I have read reports of folks who have been in indirect hits and frequently they are in shock or just plain confused after a lightning strike and this can last for quite awhile. This may have been the case for this individual. People offered to help and he refused it, they apparently reported the encounter so authorities were aware but it would be hard to force someone to be rescued if they didn't want to be.