@surgery give it time, leave him alone let him figure it out and yea its the security net of the family/parents which keeps him from realising the truths about life perhaps if u can find a way of creating situations which make him see that security net for what its worth and that it wont last forever and he will need to make one for himself, that should do the trick. trouble is that will require u to pull the rug under his feet, atleast temporarily to shock him into waking up, maybe send him off to a rough trip?
with entps thinking is weak so whatever the environment throws at ya thats overwhelming, its all taken at once. once thinking develops, ideas can be sized up for what they are worth. so entps usually need Ti to be worked on and lots of quiet time to reflect on what their intuition (their main interface with the environment) has been overwhelmed with. So Ti helps them judge stuff. Some of it comes with age and experience and some of it needs to be consciously developed. (check this out too ENFP Personal Growth)
suggesting or directing are not great ways to proceed here. maybe gift him a trip/book which conveys what you want conveyed. oh and keep at the tests and mbti bit, every few days pick it up for discussion. discuss different types of personalities, ask him to identify some of the friends and suggest how could they do things better... if it genuinely catches his interest he will be onto his case pretty fast.