I started an open mic night about 10 months ago and it's only really got going this last few weeks, so please hang in there it may take a while to pick up.
From a technical point of wiew, I have a condenser mic for occasional use on acoustic instruments but it is also great for vocals when you need a more sesitive response, it needs careful handling as it is prone to feedback but may be worth suggesting to your guy.
By the way, where is this held? You might pick up a few punters from here!!

Best of luck,

Paul.