Seems to me that you / she need to track oil consumption. Also, seems to me that you should have the right oil / viscosity in there before you can trust the results of said consumption figures.
Also, unless she has records evidencing a valve adjustment in the past 15k miles, I'd have it done. Then, you can start tracking oil consumption too (as you'll fill the system with the proper oil). I'd also consider replacing cap, rotor and plugs (and maybe plug wires too).
Also, what sump plate on the bottom of a 3.2?...
