Those of you saying that he's leaving for the money clearly have no idea what you're talking about. Theoretically, let's say he leaves for another five months.
That would be 153 days from now. On average when he was uploading daily he was gaining 1,000 subscribers per day, projecting his view at about 368k if he didn't stop uploading until then. (This isn't even counting the exponential growth that youtubers get before they reach around 2-3 mil)
Would he gain that many subscribers just by leaving and coming back? Who's to really say, but we can definitely try to predict the amount of $$$ he'd make in that time. I say "try" due to the many factors that come in to play when you calculate the ad revenue a youtuber collects such as the views, time, ads, etc.
If we take all the averages of the typical ad revenue that one would make in a day, average out his views to 70.5k and assume his CPM is around $2.00 we come out to a monthly total of $4,230 (This means that his yearly salary simply from ad revenue is equal to that of the average American household). Multiply that by the five months that you are assuming that he'd be gone for, and he's missing out on over $21k
This isn't even counting the amount he'd make from streaming, which is a ridiculous source of income. But streaming takes time, way longer than a video. If he records a 20 minute video, and generously give him 40 minutes to edit, that's one hour of work a day for the average American's salary.
So yeah, totally doing it for the money.