✔ 最佳答案
I'm not saying this to be mean, but maybe he just needs to get away from you to clear his mind and since he knows somebody there that he can use as an anchor of some sort, he went there since he has nowhere else to go.
By a certain age, people know they want to be in control of their own life, and have certain freedoms. Once a "mental illness" has been diagnosed, they automatically lose a lot of their freedom to make their own choices, sending them in a down spiral of hopelessness for their future. You, as their caretaker, become a constant reminder of that bleak future, and the feeling they will never be their own boss.
Having goals, motivation, and a plan for one's future is critical to emotional health. Feeling indebted to another, or dependent upon another can take away the feeling of being able to create one's own goals, and also deletes the motivation to achieve those goals - they don't want to have to "run everything" by their handler. They want freedom.
Can't he get into a college of some sort? Is there any way for him to go away to school?
參考: Personal experience.