He's Tweeting >500 times a day. There is almost no hour of the day he does not Tweet now. He is either paying someone to Tweet or he's literally no longer sleeping.
It's typically not that people lose the need for sleep as they older, but that aging negatively impacts the ability to sleep, which leads to individuals suffering from both age-related decline along with the impacts of their sleep's impaired restoration.
Here's a graph about third of the way down:
https://www.natesilver.net/p/elon-musk-and-spiky-intelligenc...
(Elon Musk's Tweets by time of day)