For the amount of fecal polishing required, if whatever he bought is even remotely a driver, sell it. Just sell it now, and use the money to get a 4wd version. Regardless of the fabrication skills, he will be worlds ahead by doing so and will probably save a ginormous amount of headache also.

In addition to Sean's comments about the related gas mileage, there is also the issue of relying on a highly modified vehicle as a daily driver. The amount of custom work proportionately (exponentially?) increases the amount of upkeep. Not to mention the time/money spent on putting axles under only to start stacking the miles on it by driving it on the street.

Just some ideas. Can it all be done? Yes. Might there be a better approach? Yes.

Good Luck,
Michael