if so, what is the test called and can it tell what drugs hes on??
Medicine testing, generally divided into test paper test and blood testing, test paper test nearly a week whether to use medicine, and early pregnancy test paper almost, and blood tests can for up to a month or so, test paper is divided again urine test and mouth contain two kinds, other types of medicine according to the detection is divided into single and all in one, the hope can help you.
I can inform of something you can notice. If he's acting stressed, very energetic, very tired, if his pupils are not basing on the light, for example it's bring and his pupils are big and there is no change in them.