If the work of the relatives you mention is as described, then his work is haraam and his earnings are haraam. The one who does such work has to look for another job, and keep away from haraam things. There are many means of earning a living, praise be to Allaah.
“And whosoever fears Allaah and keeps his duty to Him, He will make a way for him to get out (from every difficulty).
And He will provide him from (sources) he never could imagine. And whosoever puts his trust in Allaah, then He will suffice him”
[al-Talaaq 65:2-3 – interpretation of the meaning]
It is better for the Muslim to protect himself and to keep away from places of temptation, so as to protect his honour and his religious commitment. Allaah will give him a way out.
It is not permissible for the relatives and friends who visit them to eat their food or to drink anything they offer, if they do not have any other source of income apart from this work.
And Allaah is the Source of strength.