So I know this is in the imperative section, but is there any reason this couldn't also mean he makes a good coffee? as in WOW, he makes a good coffee!
No, it could definitely mean that as well. I imagine you'd have to use context to tell the difference. (Or explicitly say "lui fa" if there was risk of ambiguity.)
You can say fai, fa', or just fa. http://italian.about.com/library/verb/blverb_fare.htm
It's one of the adjectives that have an irregular form before the noun: http://www.arnix.it/free-italian/italian-grammar/adjectives-irregular-in-italian.php
When you put "buono" before "caffè", it becomes just "buon". If you said "un caffè buono", it would be just that, I believe.
"A good coffee" is UK usage. An American would say "good coffee" without the article.