First of all, tell him to do the MBTI test. You are not sure he is really INTP, which makes things difficult. A BA in Biblical Studies isn't the first thing INTPs go for, you know... we tend not to believe in the supernatural.
Assuming he is though, I would suggest:
- start a business, make a million (need to master a number of disciplines ranging from legal to administrative to strategic... I think only a supersmart INTP can do it properly and only an overconfident ENTJ can wing it and still succeed)
- invest the million or grow the business to make 10 millions (need to really understand money, finance, investment of at least one kind)
That should be enough for most people with a family, though he should be prepared to give up almost everything else in his life for a number of years. After he starts he may realize it's fun though; this is in the end just a system like any other... but one which feeds you, instead of consuming clock cycles and requiring you to feed it. And you're not suspending your life to do this, rather you're discovering your hunting instincts... all emotions get rewired accordingly from risk perception to one's self image. You become more alpha and confident in many ways.