New York State - Eviction

[Janitzio Santos]

Good afternoon all. My family has a bit of a situation that i don't know how to navigate.  Earlier this year my sister ended up looking for a tenant on Facebook and rented out our basement that does NOT have permits to be rented out on a verbal month to month agreement. The tenant who appears to not be employed paid the rent 5 months in advance which my sister should have found odd but proceeded to deal with this person.  About a month ago he stated that not only will he NOT be paying any future rents but he also has no intentions of moving and if there needs to be a judicial dispute so be it. He has proceeded to do drugs and create dangerous situations by leaving appliances on causing smoke detectors to go off to get my family downstairs to address the issue. He has called authorities on several occasions for harassment as my father and sister have attempted to collect rent or evict him.  I'm not sure how i should handle this as i know NYS is a tough place on Landlords and this is post covid aswell. My main reason for getting involved is due to the fact that there is heavy drug use in the apartment and my mother is a kidney transplant recipient as well as i have my 16 year old nephew living there as well.  The environment this individual has created is clearly a hazard to everyone.  Any help would be much appreciated as to what the correct steps on getting this person out are. 

Tenant is 28 Years old, Not employed, currently 1 month behind on rent on a Month to Month verbal agreement (no docs signed), Using drugs and seems not fit to be renting from anyone.