always remember that the main point of bodybuilding is to look bigger even if yuore not weigh as much as you look ,,you can be 160 naturally and look 185lb if ripped and single digit and have good wideness to waist ratio,,this still doesn mean you have bodybuilding size,,
at 5'10 inorder to look anything like a bodybuilder you need to be 200lb atleast looking like 220 230lb and walking areound preferably 10% or under,,only then you will look like what people call bodybuilder,,for that at his age hormones are needed ,,moderate use of hormones consistant use of hormones and it really doesnt matter if it is one hormone or combo but at this age he has to feel hungry and make sure that the food go to the right place,,,only thing that will bring this hunger and anaboloic distribution of nutrition is hormones,,past 25 most guys start sag,,the ones who all their life is bodybuilding and dont do anything but bodybuilding eat and sleep may start sag at 30,,im talkin naturally here,,,in any case between 25-30 naturally you become nothing and defenitrlly will never look like a massive/big bodybuilder and that means low double digits to low single digit % with out hormones and the right use of those hormones