Huh? I don't have a seven year old or a fifteen year old. My 23 year old son is living on his own in Vail, Colorado - we don't even live on the same continent. He's extremely well-adjusted and independent and has been sleeping in his own bed in his own room since he was a year old when we moved out of the one-bedroom apartment we were living in when he was born.
My 20 year old daughter lives at home but she also has been sleeping in her own bed in her own room since we adopted her at the age of four months.
And I never even had to use stickers or rewards - they just did it.
But just because my own children did not have the issues this little boy and other children do doesn't mean I can't understand that every child is different with different needs and you CANNOT expect all of them to respond and react identically to situations and stimuli.
I would NEVER lock my child in a room like an animal in a cage. If I did, I would not be surprised if that child developed serious emotional problems.