I don't think that "autism" has anything to do with it, the guy didn't seem autistic. Actually, this sort of fatalistic nihilism is rather common among "postmillenials" (born after ~1995). My cousin's two kids, ages 16 and 13, are like this. They simply don't care about anything. It's different from the "slacker" milieu of the early 90s, that one was a conscious rejection of the excessive materialism of the first half of the Baby Boomers.
Kids today just don't care, about anything. They have been told so often that the world will end in 20 years due to global warming, terrorism, overpopulation, and so on, and they have grown up under a system where the favored few literally get away with murder while the rest are locked up for life under the flimsiest of pretenses, that they don't see any reason to better themselves. After all, they will be loaded down with debt, working three menial jobs which will barely allow them to eat, only for the earth to go insane and kill them all within a few years, so why should they lift a finger?
It reminds me of the attitude of the young Argentines who grew up in the wake of their country's total socioeconomic collapse from 2001 onwards. All the kids do is smoke "paco" which is actually the waste product from cocaine processing. Paco makes its users extremely, unpredictably violent, like flakka only far worse, and the kids slaughter people indiscriminately before dying themselves within six months. And that's not a problem, in fact it's the whole point. Go out in a blaze of glory.
It reminds me of Albania after Hoxha died (1985), there were roving gangs of youths killing people at random and finally the whole society imploded in 1996 and people looted armories and started killing each other for fun. In Argentina it's called "estan jugados", literally "they're played out", meaning that the kids had the dice thrown for them before they were born and they lost.