His meter was reading 1.008 during the hypo salinity treatment, but was 5 points off. This means the water was actually 1.013, which is not low (hypo) enough to kill ick. His ick came back.
Now think about this: if the meter was showing 1.024 before he attempted hypo treatment, and his meter was 5 points low, his tank water would have actually been 1.029... which is hyper salinity... which would stress the fish, weaken their immunity systems, and make them vulnerable to ick.
Of course, none of this is relevant to what is happening because he hasn't accurately calibrated his refractometer. You can't do it with bottled water. It may be off by far more than 5 points, or it may be dead on. We won't know until he checks it with the right solution (distilled water or calibration solution), which work on the same principle. Solution has a specific amount of gravity, which you match your refractometer to. Distilled water has zero specific gravity, so you match your refractometer to zero. Waiting for the update...