They can work. My daughter was in an Residential Treatment Center (RTC) that helped her tremendously -- at least the running away, stealing from others and cutting school stopped. It didn't stop her from quitting high school the first chance she got. It didn't stop her from lying every time she opened her mouth. It didn't stop the manipulations and bad attitudes. It also taught her how to make friends, make less-risky decisions and helped with bonding to an extent.
I can tell you that I very carefully explained to my daughter why she was going to a treatment facility. I think that on an intellectual level, she understood. However, emotionally she either did not understand or she simply uses it as a tool against me. Not sure which.
Do research it carefully. First, make sure you have an accurate diagnosis for your nephew. Then, find an Residential Treatment Facility (RTF) that deals with that the type of behavior your nephew is engaging in and that knows how to treat for his specific diagnoses.
I would not recommend a military school for a damaged child. The odds of him staying there are slim -- either he will be expelled or he will run away.
