Kicking tenants' friends out in nyc

[Meng W.]

Hi BP,

I wonder if there are any guidelines or rules for the landlord when kicking tenants' friends out. for instance i have a tenant whose mother is extremely irresponsible for her children who are over 18 years old. Every night the kids invite their friends over to talk on the terrace and smoke weed. Am i allowed to kick their friends out even though the tenant allow them to stay? Keep in mind these kids are smoking weed and talking after 12am every night (waking me up). Does anyone know the rules to smoking weed in general also? I know when a person gets caught he or she is issued a fine nothing more.