Maybe if he was positioned nose-first he wouldn't have had the rear outriggers act as a fulcrum. Even if he had to position the pool where he dropped it in the front yard or the street and then staged again to allow the crane to keep the wheels 'on the ground,' so-to-speak, it would have ended better. I have other opinions on how to do it correctly, below.
I am not an operating engineer, but I was qualified on the job as a 'driver-engineer' which included operating every piece of firefighting vehicle in our inventory, including the Ward-LaFrance 85' elevating platform w/a wet-pipe master stream (min. 300 g.p.m.). To properly stage that for operation, you actually used the hydraulic outriggers to their fullest extension out from the side of the body, and then you actually lifted the entire truck off the ground before you were ready to use the elevating platform or the wet pipe which was plumbed to the top.
If you did it correctly, there were spirit levels to indicate you were within the range of operation, and that you had staged properly. There was an interlock to prevent the platform from operating if there wasn't pressure on the outriggers, this was due to prior accidents well-documented in the fire service where aerial trucks toppled because of incompetent operators "trying to argue with Mother Nature" & defy the Laws of Physics.
Whoever was the engineer of record for that job should have calculated the lift requirements prior to that siting being attempted. Bottom-line, the truck was too-small for the lift, the company tried to cheap-out instead of renting the proper equipment. I bet their insurance company denies the claim because they didn't engineer the lift properly. In plans review, those are the things that get addressed, so there are multiple people who screwed the pooch on this one.
One of my neighbors is a G.C. He just this past year built a pool on top of a penthouse apartment on Miami Beach. I am a plans examiner, and he showed me the prints of what reinforcement the building had to have for the pool to be placed. The pool was airlifted into position and bolted-in, because it's in a 'high-velocity hurricane zone' the entire project has to be capable of withstanding gusts of 150 mph. They had an 'over-engineered' product every step of the way, and the insurance that they had to carry was $$$$. It came-out beautifully, and it should have for what it cost. He got multiple jobs out of people seeing what they did at that one, and now he is commuting between both coasts doing similar projects and others. It took longer to do the permitting with the city and the H.O.A./condo board than it did to build it and get a certificate of completion signed-off.