that's cool ade
maybe you could make it like a chat thing so its not too formal? By this I mean you can discuss with him and record the conversation and then you can arrange the text to get out a few important questions...
When did he start making music?
What are the bands he respects the most?
What is his synthesizer of choice?
That's what i got on top of my head, but feel free to ask more things.. as I said if its a chat thing its cool.
Good luck with it