should needy families be required to take drug tests to receive aid?

Actually, this might not be a bad idea - at least to see if they are complying with rehab programs, etc. I'd like to see this done with people who have qualified for disability due to addiction. But, as you said, it is complicated because it runs the risk of harming the rest of the family because of that member. But, yes, I think it might help more people get the help they need if they know someone is going to regularly check on them.