Prenups help protect what you BRING INTO a Marraige, not what you make during the Marraige.

So say you have an antique watch given to you by your grandmother, worth 20k. A prenup would help protect that asset. Keep it separate from marital assets.

If you buy a fancy painting for 10k while married, that's considered a marital asset that belongs to both of you. Regardless of where the money came from. The US see's marriage as a 'joint effort'.

Also any prenups that scew things in drastic favor of one person over another are usually thrown out. If you have your future wife sign a prenup that states she will get absolutely nothing in the case of a divorce, and just get kicked out of your house, well a judge will throw that right out the window.

I know thing seem unfair for your friend. But you have to remember he let himself get put in that situation. He wasn't forced to be with a woman that had no ambition, or drive. He allowed that to happen. I'm not saying it's right, what he is currently going through, but at the same time, it is legally fair.