Yes, Dr. Raju seems to be extreme in some aspects, for example: avoiding salt altogether.
And I read that not salt (especially while drinking so much water per day: 5 liters) can definitely upset your electrolite balance. And that could lead to very serious complications.
Batmanghelidj recommends to drink only half your body weight in ounces a day ( if you weigh 200 pounds you drink 100 ounces of water a day), he also says you “MUST” take some balanced sea salt, 1/4 to 1/2 tspn a day depending on the amount of water you drink.