Yes, from what I read he has supervised a lot of fasts less than 30 days. The thing he seems to be insistent on is letting your body decide when to end the fast by waiting for the return of hunger.
Also, the talk of "people have died on Shelton" if you read what he says was due to improper breaking of the fast. Which is why he is so insistent on starting with juice and slowly progressing towards solid food. Your stomach isn't able to handle whole foods at the end of a fast (if over 7 days there is no intestinal flora to aid in digestion, etc).