It has very, very little to do with lack of jobs.
If they're that poor, how can they indulge in drugs, ciggies, booze in the first place. When you give them more money, what do you think they spend it on? Drugs, ciggies, booze.
How on earth does lack of money lead to kids throwing bricks through windows or lumps of concrete from bridges onto cars below?
Most of them are completely unemployable in the first place.
You do realise that each worker will not only deal with that family, but others as well. The idea is that the family will only have to deal with that one worker, rather than several