While the analysis by WP and Joomla as projects is that the PHP in themes must be GPL (I'm not going into an explanation of this), the other parts of the themes, assuming they stand alone, are not necessarily GPL licensed. So theme makers may be able (or even required) to restrict distribution of those parts of the theme. Further those elements may have their own licenses.
Without going into all the gory details, depending on the template, your friend may or may not be able to give you the full source code for every single thing or all elements. Likely the friend can give you some pieces of the source code.
Of course, if all elements of the theme are under the GPL then the GPL applies to everything. In that case you friend can pass on everything.