A lot of posters in here, including you, Sohei, might try reading the article. I'm guessing it was the $37k/yr apartment that his parents were paying to rent that had his entitlement jimmies in full rustle, not the $200 (originally reported $100) cut in allowance per week. BTW, $200/wk works out to $9,600 a year. That might not be much in NYC, but in places like my hometown that's about 1/3 the median salary. It's nothing to sneeze at. Poor people commit atrocities against each other for far less all the time.
This kid was getting subsidized to the toon of $56k/yr by his parents not counting whatever else they bought for him or spent on him: just what is reported here. I have a suspicion that he probably didn't own a vehicle, but had one all to himself; that he didn't pay to gas this vehicle, or for its insurance; probably an unlimited metro card, too; that his parents probably sporadically bought him clothes & furnishings amounting to thousands of dollars each year, replaced or fixed appliances, his medical bills, etc. I'm willing to bet that his "allowance" went almost purely towards food, alcohol/marijuana, hair cuts, additional clothes & amenities, and sundry other purely elective expenses of entertainment and luxury. I'm betting that the total sum they spent on him was probably closer to $100k-$150k/yr. He's living on that without an ounce of work. He doesn't even have to show up to a government office and stand in line.
It sounds to me like he turned 30 and his parents probably deliberated and fought over how to proceed, but ultimately decided that they needed to effectively cut him off from this lavish lifestyle in order for spur him to take responsibility for himself. It appears that he was unable to handle this, and took it out on the very people who loved him the most and contributed the most to his life.
I suspect that there will be an independent film about this waste of space in the near future. All I can say is that if I was a security guard wherever he is imprisoned, and I saw him getting gang-raped in a shower, I'd grab a coffee and go read the paper.