Sorry, Dream. "Do nothing" is exactly what you told him to do for his abs.
OP asked how to get "rock solid abs"
you said: "No exercise necessary. Just a sustained calorie deficit. How long that takes depends on how much abdominal fat you have to lose."
After he explained he has a flat stomach, you said: "No problem. Flat abs are good. Apart from fitness models and bodybuilders, almost no one needs a six-pack. The difference between flat abs and a six-pack is usually a few pounds of fat."
Then I went ahead and replied. Your answer is obvious. Of course you need to lose weight to see your abs. 1st graders know that. But the OP wants rock solid abs.