according to google in nyc if you are still in the home for 30 days after the eviction notice then you have squatters rights to the home in which case the landlord will most likely have to file some court papers to have you removed. but eventually (probably like 2-3 months tops) you will be removed from the home by the police.
generally i dont recommend squatting somewhere where the landlord is aware of whats going on. but basically if you arnt removed by the cops before 30 days is up you could possibly have the place for another 2-3 months. keep in mind if the landlord looks at his place 1 day after everyone is supposed to be out (say to change the locks or make sure the place isnt trashed) and you and yer buddy are still hanging out there, he will most likely call the cops on you and have you charged with trespassing. remember before 30 days are up you have no squatters rights therefor no right to still be in the home, so yer one visit from the landlord away from being boned. best of luck though.