I'm sorry for your friend. The reason you can't find it in the bible is because the jw's really rely on the watchtower literature rather than the bible. It is supposed to be a conscience issue but as most on these boards know if your conscience doesn't match that of the elders & wt you will have problems.
Again, I am so sorry for your friend. Let him know about this site so when he is abandoned on a regular basis by his jw he will have somewhere to turn. I hope he does not plan on having children anytime soon with this jw!