Yes, DAA, Unleashed(SHBG inhibitor), an herbal test booster couldnt hurt. Make sure that there aren't any hormone based products in it.
Some Phytoserms-347 looks very promising. I have heard great things. It is used alot DURING PCT, so I dont think you will have to worry about running a pct afterwards.
It will boost test along with lowering shbg. A friend of mine told me its the best test booster he has ever taken.
But really, your options are kind of limited. Unless you wanna start messing with your sons hormones, there isnt alot out there that will safely and effectively boost test to a noticable level.
daa, unleashed, creatine, glutamine, bcaa's, protein, hmb.....I cant think of much else right now
You have to remember that his test levels are about the highest they will ever be naturally right now. I think males usually top out at around age 24. Granted they never messed with there hormones at a younger age. That being said, there really isnt much out there that will "boost test" without messing with his hormones, his test is already sky high. An herbal supp like Phytoserms-347 or maybe some HcGenerate will probably be his best bet. But even that might be too strong if your saying you dont want to mess with his hormones. Im just not sure if they can be used by a 17 year old kid without the need of some sort of pct. Look more into that. Use the search feature on this site. And hopefully someone will chime in with more info on these products being used standalone by someone under 20.