Your cousin brother is mostly correct and ASR just reports the measurements - good or bad. We know what distortion is audible from measurements. If it doesn't pass that threshold then by definition it is inaudible. Measurements will show that. I don't know of any DACs today that have audible distortion. Almost all DACS use the same digital conversion chip. And the formula for analog conversion is also well-established. As a former software engineer I can tell you that conversions are always done by using a well-established formula. Otherwise, they're just plain wrong. There's no magic to it.
However, some DAC makers purposefully make their DACs inaccurate. If you read the book Schiit Happened, Schiit actually tweaked their analog conversion programming after listening to the output through headphones, which is purely subjective. This shows up on measurements.
Personally, I use an SMSL Sanskrit 10th MK II because it has the best measurements for the lowest price.