I played high school sports in texas between about five and nine years ago and steroids were as big a hot topic as they are now and as they were 10 years before that.
Andro was the big thing at the time and threats were made regarding it when i was there too. I used it, most of my buddies used it and none of us were ever tested though threats were made pretty much once a week.
Maybe your son will be tested maybe not. I doubt it. and if he is I doubt if any supps other than the purported test boosters will show as much of anything.
Proteins will be fine. It is just protein. Chicken won’t set a test off, neither will whey.
Creatine won’t. Fish oil wont. Vitamins wont…
maybe tribulus, dhea etc, but he doesn’t really need to be using that stuff right now anyways. (foot in my mouth?)