So it 'Whirred ' when he Hot wired the Starter (like the starter was spinning but not throwing the Gear forward to the Flywheel)?

That sounds like a different issue then the Slow crank mentioned.

From your first Post, I too, thought bad Battery connection, now I'm a bit thrown by the Starter spinning but not engaging.
With the battery replaced just three months ago, I would check the Battery connections. If he had the work done, it's possible the guy with the
Water-Pump-Pliers working on the car didn't tighten them very well.

Just remember it takes A LOT of Current to spin up a Starter. Running the lights would tell you if your battery is in very bad shape. But a bad connection might run the lights fine but not have enough connection to carry the current needed to spin up a Starter fast and hard.
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'75 Jeep CJ5 345Hp ChevyPwrd, two motorcycles, '85 Pickup: The '89 Volvo is the newest vehicle I own. it wasn't Volvos safety , it was Longevity that sold me http://home.no.net/ebrox/Tony's%20cars.htm