Earlier quoted context omitted.
I think I heard this in some Peter Attia podcast. The kidneys turn salt into fructose as far as I know. When u're diabetic and you consume salt it's much better to have it in liquid form. I don't think the reasons are known, but it doesn't raise the serum sodium as much.
None of what parent said in any way resembles how kidneys or even biology in general functions.
Dr. Johnson doesn't mention what organ in the body performs the conversion, but he does mention that high serum sodium activates an enzyme which converts glucose to fructose.
Fructose, in high amounts, causes high uric acid, leading to inflammation, insulin resistance, and causes the body to switch from fat-burning to fat storage (bears and migrating birds will increase their fructose consumption before hibernating/migrating).
According to Dr. Johnson, if you eat some food and feel thirsty, that indicates that your body has already started converting glucose to fructose internally. Drinking enough liquid to keep the serum sodium from increasing will prevent this conversion.
from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3833672/ (Dr. Johnson is a co-authour of this article) "... activation of aldose reductase in the liver with conversion of glucose to fructose"
Then I found this article, https://www.hindawi.com/journals/ijn/2011/392708/, which states that "The increase in dietary fructose intake stimulates salt absorption in the small intestine and kidney proximal tubule through coordinated activation of PAT1, NHE3, and Glut5. We propose that reducing dietary intake of fructose and salt, as well as maneuvers aimed at inhibiting fructose absorption in the intestine and kidney tubules, could have profound beneficial effect on controlling blood pressure in patients with metabolic syndrome."