Working in property management, I see shit like this ALOT.
People renting houses, kids don't want to move, etc etc. Parents think because we manage the property they put their own full-grown adult on the lease, that we magically can do something about it. He's on the lease, we can't do anything.
We've had parents renting apartments just for their kids to get them out of their house. (Surprise surprise, these are the same kids that call maintenance to change a fucking light bulb because they are scared of being electricuted. Don't overshelter your kids guys, or this happens.)
As for myself, my situation is pretty weird. My mother has been a single mom and always struggled. I still have an underage younger brother, and my mom isn't ready to clear house just yet. When I was in the military, she had my two younger brothers to keep her sane. Now my younger (not youngest) is in the military, and she's had a hard time clearing the nest. I pay a majority of the rent, bills, etc, so she can focus on my youngest brother and they still have that family feel. Granted, my girlfriend and kiddo live with us so its a rather big 4bedroom to accompany everyone. It keeps my mom sane because I help her out with bills and everything. She doesn't have to flood 60+ hours at work to afford to take care of herself and my youngest brother. My girlfriend gets to stay home with my kiddo because my mother helps me as well. My girlfriend loves it and so does my kiddo. It's a team-effort here, lol. Granted, Jan of next year, we'll be splitting our separate ways.
I can understand the struggle of someone trying to go out on their own. I got blessed with a good job at a young age, but plenty my age are still struggling to even find a job giving them over $10/hr. They need a decent deposit (~$300-$500 for a low-rate rental, more if you need better quality/area), first months rent before move-in, money for furniture, money for food, money for all the utility deposits (and if you've lived off mom/dad name all your life, these are about $100-$300 each.) Now for the renting, you need 2.5x the rent in most places, and good credit. Kids usually have no credit, so they need their parents or someone older to vouch for them. If you have parents unwilling to do that, it's rough. I've seen kids come into my work, brand new 18 year olds, parents told them "you're 18,. out you go" and they have no idea what to do. You can't expect an 18 year old to immediately have $2,000-$3,000 saved up, have decent credit, make 2.5x average rent alone (usually $2,400 a month in income) and know how the world works.
On the opposite note, at 30, your shit should be together at least enough to get an efficiency. I don't have too much time to read the story, but if it is just him, by himself, no kids or girlfriend, no extra expenses. It isn't unreasonable to think he can tackle an efficiency. Though this is NYC and rent there is monstrous. Maybe hit the island for better rates.