Trying to help ADHD Grandson

I don't have ADD but I wonder if I'm a "carrier" as there are a great many people in my family who show signs of ADD. A bit of background:

My daughter, now age 30, clearly has a galloping case of ADHD. Very bright, she dropped out of high school in tenth grade because you couldn't tolerate the frustration of classes she already knew the answers to. She was a difficult child. She would stay up all night, sleep all day, not go to work, use drugs, hyperfocus on friends. She got pregnant when she was 15. Nothing I could do worked. She left out the window when it was time to leave for counseling appointments. When she was 20 she lost her Section 8 house and lost custody of her son to her sister. She works in fast food. She is so bright that she passed her GED without any classes or even a semester of high school.

My other daughter is the total opposite. A successful lawyer, happily married, homeowner. She ended up with custody of her nephew, my other daughter's son.  He is bright and seemed to thrive with consistency and ADHD meds. But now, at 13, he is sabotaging himself. He gets up in the middle of the night and breaks into their computers to use Facebook. He looks at suggestive pictures on the internet in the school computer lab. As my daughter says, he never thinks before he acts. She calls it "point, shoot, aim." Now they are applying to military schools, which his therapist endorses. They have asked his biological mom "what would have worked with you at that age?" and she says "nothing." I do not want him to end up like his biological mom. I don't want a future granddaughter-in-law to end up like the wives on this site (including me). Does anyone have any ideas. My gut is that the military school idea will not work, but I don't know what will.