How would you teach someone vocab pronunciations?

Repetition, repetition, repetition. I used to teach English at a Berlitz school in Berlin. The method was short questions and answers over and over again, so that students repeated words, phrases and sentences listening to the sounds, but not seeing the words, so it was all oral and aural. No writing, no looking at words. 

That is how children learn to speak, and it works for adults too. 

Make him an MP3 in the I say, You say format. Pronounce words properly, then challenge him to mimic your pronunciation. Give it to him/her for practice, then quiz him on words that are on the disc by giving the proper pronunciation. If s/he does the homework, it ought to show in the drill.