The kid at the door won't let you in no matter how you rant, cry, or threaten. Argh!
Hint 2
Eventually, you'll have the option to "ask for help," and he'll be slightly more helpful.
Hint 3
He tells you the name of someone else who lives in the building who might vouch for you, and with a little more pushing tells you where she is right now. That'll have to do, I guess.
Hint 4
After you "restate the obvious" and "grudgingly take your leave," go left to exit the scene, then head for Washington Square Park. Walk left past the dog park (ow) and left to exit past the fountain, then walk right past the dog to find Nishanti.
When Nishanti returns to the apartment building with you, say anything you want to the kid at the door, then go in. After a little more awkward conversation, you're FINALLY home.
Hint 6
But rest is a long way off yet. Inside your apartment, the phone rings; answer it to talk to your late aunt's doctor.