You need to find the positives in his style of drumming and let everything else fall away. If he's really loose to the point of absurdity go with it...100% and incorporate it into your sound. If he's incapable of hitting hard enough or lacks stamina that's a different matter, give him the boot because those are things that should only apply to new drummers. Other than that, accept his style and accentuate it. If he turns up on time and is into what you're doing hold on to him.