enough with the Flight Sim talk
The Captain did not "build" a flight sim, that is Microsoft flight simulator 10 and is a very popular software. He probably used it to hone his skills. The add on software is quite good at replicating the systems of a t7 or many other aircraft
He certainly put it together from parts he ordered, he posted pictures on his Facebook page. I commented earlier on the domestic U.S. Mail Priority box, it looks like he had some of the items delivered somewhere in the States for pickup.
He had a high end Asus motherboard, a 1000 watt power supply and multiple Nvidia video cards in the upgrade to his existing homebuilt computer.