Even so, your conclusion must be wrong. Regardless of whether the disc can be read or not, ESR should display its splash screen before trying to read the disc. Since that splash was not displayed, I think that ESR was never started...
He has everything configured correctly. I think his problem is his PS2. He's trying to play Kingdom Hearts 2 Final Mix on a burnt disk. The disk is set up correctly, I know this because I made it for him. I even tested it with ESR on my PS2 and it works. I think because his PS2 is old, it won't read the disk. It has trouble reading anything that isn't a PS2 disk.
Yes, of course uLE can launch it, but ESR will only work right if you booted uLE with FMCB, as ESR depends on some CDVD initialization that is not done by most other booters (modchip Dev2, or SwapMagic, etc).
So, is it his PS2 like I'm suspecting? If it isn't, is there any other possible way to load ESR or the game? Will ULaunchELF load ESR?