Welcome bro...
As for your question tren ace can be detected upto 4-5 months out
link:
Steroid Detection Times of Various Anabolic Steroids by Steroid.com
In any case him being 19 is more reason for him not to do steroids due to many factors including that he already has raging hormones, lack of research and the fact that taking steroids this early could result in stunted growth.
I agree aspirating isn't a myth.. Its essential.. especially when the person injecting isn't trained and he doesn't know where the main veins/arteries are.
I don't see the advantage of running a weak oral at a high dose... Instead use a stronger compound at a lower dose...
Max dose for anavar (And I'm stretching it here a bit): 80-100mg ED