overnight snack for teenage boys; exercising; confusion

Please, is there someone who has experience with overnight nasogastric feeding tube (in AN indication). Our GP who is a friend and great doctor (and my father's university girlfriend) thinks it would be really beneficial for my brother. He is eating now hardly 2000 kcal and struggles a lot with this amount what is for a 180+ cm teenage boy (with some perspective of growing more) really not enough. GP suggested this AND his psychiatrist thinks it could be the only way how to avoid inpatient. The really weird think (from my perspective) is that the psychiatrist thinks M. should have the tube AND exercise regularly EVERY DAY. He said M.'s muscles are really wasted and he is so depressed because he is so inactive. The thruth is he is hyperactive, just not physically. He spends like 8 hours a day with schoolwork, meals take at least 4-5 hours (no joke:/) and he studies another 4 hours after dinner reads or writes some stuff (part is schoolwork, part is some kind of diary I think). Yep, there is not much time left for another activities (considers there is usually at least 1 hour of panicking or just sitting and shaking after one of the meals). Approximately 5 hours of sleep (and you know the quality:/). This IS hyperactivity. It is not overexercising, but I am afraid that any kind of exercising could quickly become new (and more dangerous) kind of hyperactivity. So I am bit confused about this exercising-as-a-therapy. What do you think?

There is this "detail" what does brother think. The fact is he is just confused. You can see he is unhappy and trying to find a way out of this all, but at the same time he is passive-aggressive when someone breaks his comfort zone. He doesn't say no to the feeding tube and actually he looked relieved when he refered to me about it as a "refeeding without guilt of eating", but his moods are so unstable that we can't predict what comes next. We didn't discuss the exercise think yet and I am certainly not the right person to do it, because it is really "hot potatoe" (as we say it in swedish) topic.

Ufffff.
Better news: another state exam done = just one megagigahyperbig + one rather easy exam to do and... we will see. Have a good week!