I have no doubt of your affection for your friend, as demonstrated by your dedication in pursuing this matter with me personally. Your devotion is admirable and Mr. Lupin is a very fortunate young man indeed, to demand such loyalty. Your testimony to his character is one that has certainly been mirrored in my own observation, and I find Mr. Lupin to be a very promising, very intelligent individual whose talents will be certain to provide him with great success no matter his chosen career, in the NAA or otherwise. I hope you can understand, then, that as someone with similarly great respect for Remus Lupin, I cannot order him to return to Hogwarts at this time.
Though I do not question your intimate understanding of the many facets of our remarkable Mr. Lupin, I am afraid that I cannot simply accept your suggestions on the merit of your word. Mr. Lupin has expressed no such sentiments to me or to anyone affiliated with my office, and although I appreciate your attest to his humility, I can't presume to know Mr. Lupin's thoughts unless he speaks of them to me personally.
I can say that he was offered the option when I spoke with him in England of either deferring induction until the completion of his Hogwarts degree or sitting his N.E.W.T.s early and beginning training immediately -- and he chose the latter. He has already begun his classes, and though typically we would not allow a student to leave mid-term, you are quite correct in saying that I would hate to unwittingly be holding a young man here in Germany against his will. But it would be an equally egregious offense to pressure him into quitting his medical studies prematurely, if that is not his wish. To ensure that no intrusion upon Mr. Lupin's will is in occurrence, I will make him aware that the option to return to Hogwarts is still available. (Though I do warn you, the paperwork involved in such a choice may be a deterrent to him in and of itself.)
I hope this alleviates your concerns somewhat, and wish you a very fruitful completion of your own education.
Federal Chancellor of the Neuen Assistentenauftrag Berlin, Germany