10 Silverado 4.8 ECM

I have always been a shade tree mechanic interested in this stuff and do understand mostly how the computer works. 
Recently, my sons 10 Silverado 4.8 started missing bad, the injectors on the passenger side stopped firing. Took it to a shop by work and they said it was the ECU. However, they said their computer could not “flash” a replacement for this model truck.
I found several companies online that sell a refurbished ECU for this truck. However on one it stated the truck may or may not start after and if not, may need a security relearn procedure.
I started reading more and the best I can tell, you can purchase a J2534 connector that will connect the OBD port to a laptop. From there you can purchase software on the ac delco site to do the security relearn.
Do you know anything about this and what equipment and software I would need?
Any help is appreciated!
 

This video is pretty recent (things change a lot), and there's a few SD videos of Paul loosing his cool programming GM 'puters.
The investment required to program one computer far outweighs the cost of having it done at the dealer or having a mobile specialist comes out and do it.
The Snap-On Pass Thru IV (cardaq) that I use was $1700. This is the interface between the car and your laptop.
Then you need to download and install the drivers for the tool, then download the GM program, and then purchase a "VIN slot" for the car...
I charge $100-$150 to do it depending on how far I have to drive and after a few years of casual programming have still not recouped my investment.
That said, there is a process that may work on your truck, older GM vehicles only needed a 30 minute relearn to get them running.
Turn the ignition to START and wait EXACTLY 10 minutes (the theft light should go out), then key off for 2 seconds. Then key to ON, wait exactly 10 minutes for the light to go out. Key off for 2 seconds, key on for exactly 10 minutes. When the light goes out the third time, key off, then it should start.
Any deviation will result it needing to start over, so this 30mim game can take some serious time out of your day.

One of the problems is I live in a secluded area and not a lot around me.
What are these for?
STHRAGE Mini Vci J2534 Programming Diagnostic Cable Techstream Software Compatible for Toyota Since 1996 TIS Techstream Diagnostic Communication protocols USB to OBD2 16pin for Win7 32 bit a.co/d/69eI6Po

I'm not saying it CAN'T be that easy, Forscan for Ford has some powerful functions you can access with a similar Chuck-E-Cheese cord and app, but I haven't seen anyone program GM computers with anything less than what was in that video I shared.