Do it likethe goodman you are, and youll be happier in the long run! Tell the father in law that you digressed to a moment of being a sh*thead and while in that state, the dog got after the skull. He'll be mad, sure, but life will go on (maybe not for the dog though). Then offer to get another real skull, and set his antlers, on pins, into that skull. A little blending at the bases underneath and bingo!, its done. If its a true horn mount, thats just a small amount of skull anyway. If you mean a skull mount, do like I said above. He will get over it. If not, tell him he never sees the grandchild again. See what a little leverage, ingenuity and assertiveness will do? Hey guy, good luck with that, and in the future, never leave someone else stuff out when theres dogs OR people around!