RE: Tim-bor, antifreeze and water?

If I am not mistaken, the Tim-bor is used to treat wood to keep Powder Post Beetles out of the wood or to kill any that may already be inside of the wood. Since this piece of wood most likely has not been kiln-dried, it can and may have more than one type of active wood destroying insect in it. I would say that he has done you a favor!