Actually, all this type of turkish sentences would be more like "The director will drink the coffe".
Check out this quite comprehensive list of uses: https://www.duolingo.com/comment/8649253
In this course, we have stuck to simple present due to the difficulty in adding every alternative and to prevent Turks learning English in the reverse course (which shares sentences) from getting too confused. As you get to the aorist tense skill, things are better explained and we become a little more liberal. :)
The reason is that by the use of "kahveyi" instead of "kahve" you are actually talking about specific coffee. So the definite article "the" must be put before "coffee".
We have been given two words with the meaning "director," yönetmen and müdür, and Google translate gives similar meanings. I would appreciate if a native speaker would explain any difference in meaning. Teşekkür ederim!