Each unfortunate situation of someone going off the derech has a different cause. There is no common denominator. One went off the derech because the parents were too strict, and one went off because the parents were too lenient. One got pulled in by bad friends, and one was abised by his rebbi, and another became addicted to dangerous technology.
I admire the people that work with these children and try to bring them back, but I am not sure that there is a one size fits all approach that will work here, unfortunately