Debating with a creationist is actually really easy, because they only have a few standard arguments, and haven't come up with any new cogent ones for some time. These standard arguments have been published time and time again, and a practiced creationist can handily draw them like a six-gun at the drop of a hat. All of their arguments are silly in their wrongness and easily debunked, and if you're prepared in advance, it's easy to beat down any creationist with a quick verbal body slam. You're not going to change their mind, since creationists do not base their opinions upon rational study of the evidence; but you might help clear things up for an innocent bystander who overhears.Sadly, he is right. You probably will not change their minds.
Hat tip to LGF.