Broke my water pump bolt. Now what? (Update - broken bolt is out)

No that will actually get him an oversized hole .
When you drill and tap a hole the drill size for the tap is smaller than the listed thread size.
As far as the vise grip truck, if he's EASY with them so he don't mess up what's there he might just be able to walk what's left outta there especially if the reason for the bolt breaking was corrosion to the water pump which is now not there it may be pretty free in the block