Son in Brooklyn group rental:advice re legal obligation

[Julia Norton]

It has been years since we last owned a rental so seeking UTD advice/suggestions. Children are in their 20s so have been dealing with the typical co-signing for leases. Our oldest lives in Brooklyn. Had a nice group apt but at end of lease landlord booted everybody with plans for a significant rent increase. With little time an agent found him a room in a group apt. It appears to be common for many of the buildings to be divided into many rooms boarding house style and you pay for a room w shared common area. There are 5 in the apt. He is working steadily and has paid and will continue to pay out the remaining 6 months. Currently he believes 2 have not paid and they have been absent as well. The lease is standard boilerplate claiming both individually and collectively responsible for the rent. We are not sure how this will play out and if the absent tenants will return. Any thoughts(given NY location) whether the landlord can come after us? I assume he is obligated to first sue the missing tenants and their parents? Everybody was required to have a co-signer so we are on the lease also. TBH he does not know the other tenants at all or even have any contact w the owner . We do know that the landlord is Hassidic-don't know if that will contribute to communication issues either? By the way we have no problem living up to our end on this nor does my son.