They send tickets for Hajj to their parents who perform Hajj, while some of them know that this money has been gathered from selling drugs. Is this Hajj acceptable or not?
Is it permissible for Muslims residing in a non-Islaamic country to form a committee responsible for determining [the sighting of] the crescent of Ramadhan, Shawaal & Dhul Hijjah?
Proceed with calmness and tranquility up until you enter their land, then invite them to Islaam and inform them of what Allaah the Most High has made obligatory upon them.
So the call to Allaah can be to a single individual or to a group of people in the Masaajid, in club organizations, in universities, in schools or any other place.