Honestly, I'd strongly consider hiring a consultant. Otherwise you're just as likley to get bad results as good. But it also really depends on the level of expectation. Are we talking true isloation (which will require significant investment) or merely mitigation? In my life as a consulting structural engineer I had several experiences with clients wanting anything from mitigation to complete isolation. Migitation was generally desired by developers of multi-unit complexes where sound transmission (to suome degree) is acceptable but paper thing walls are not and I think this is where you're heading. The only person that I ever saw successfully implement isolation was Hughes-esque private masion that I'm quite sure is not what your friend is considering.
To get an idea of where to start search for something like "STC rated assemblies" and have a look at this http://www.usg.com/rc/system-catalogs/acoustical-assemblies-en-SA200.pdf. Skip to the end where you can see some typical construction details.
There is a minor tangential concern with how much weight you might potentially be adding to the first floor framing (basement ceiling) if you really go whole hog and start adding a bunch of shielding material.