It's not an issue of centerline here...it's an issue of oil seal fitment with the tapered bearings he is going to use. The axle may be true to the centerline, but the seal is located in the housing. It'll be a leaky mess.
Besides the point, I've seen housings narrowed with a slight amount of overlap to make up for a slight bend, but what he's got there is huge. If it was that far off, it should have been tossed.