A School for CS Rate

I have a question.  My son graduated boot camp and is at Fort Lee in VA to go through his CS training.  Evidently one of the Petty Officers told them that the CS job is the hardest in the Navy and they have CSs that jump over board or go crazy . . .etc. etc.  Is that just a bunch of BS?  It sounds like the kind of stuff they say just to get people to quit.  I'm tempted to tell him to just ignore it and move on.  It really to me just sounds like the kind of stuff you say to weed out the weak ones. I appreciate any insight that I can pass on to my son.  I have looked through the material they expect you to know for the tests and while it does look like it will be a hard job . . it hardly looks like the kind of work that would make you want to jump overboard.  Actually it doesn't look that much different then running a high capacity restaurant.  Doing inventory, planning menu's, ordering supplies, cooking meals to spec., Understanding the basics of cooking.  I'm not seeing what the Petty Officer was getting at.