Kingfish,
Its hard to discuss a vehicle I know very little about and have never seen, but:
Synthetic oil won't fix a worn, old or damaged engine (not that your friend's engine is, just a general comment). Synthetic oil, since its much slippier and it flows into small cavities better, will leak out of small gasket leaks more than regular dyno juice.
My wife's Pathfinder had +96,000 miles on it before I switched it to Amsoil. It, too, uses about a quart a month also, but it did it with Castrol GTX also, so it had nothing to do with regular vs. synthetic. With the Amsoil, I don't have to worry about when to change it, just check once a month and change it with the seasons (once in the spring, once in the fall, pretty simple).
BTW: I am an Amsoil dealer and no, I cannot give you my dealer # since I am using a Company PC and cannot use it for outside work (there's nothing stopping me from giving an opinion however, on my own time).
Regards,
Merlin