Try getting your hand slightly damp, and then petting him. That will remove a lot of the loose hair. If you do this regularly, you may not have to brush him.
However, moonchild raises a good point, not all rabbits should be brushed, as it can have adverse affects on the fur. Any kind of rex (standard or mini) should not be brushed, unless you don't care about the fur.
I'm not sure about the cat hairball forumla, but I know that fresh pineapple juice or papaya tablets are very safe and will help destroy hair blockages. And lots of hay will have similar affects (though if you're really worried, papaya tablets or pineapple juice are the way to go).
Again, how often they shed is totally dependent upon the breed and hair length, etc. I find that our Mini Rex barely shed once a year. However, rabbits with longer fur will most likely shed a little more often than that.