Solidworks version problem
Directly, no you cannot save a solidworks file to an earlier version. you CAN save it as a STL, IGES, PARASOLID, ACIS, or some other standard, (which is much the same as what the previous poster suggested using xchangeworks I believe) but the resuting geometry will no longer be parametrically editable. what you can do is save it as an edrawing and have him download the most recent edrawing viewer. this should solve the connectivity issue as long as you don't need him to edit it.
This is a major pain in the butt with solidworks and I have ranted to everyone in the organization including the head honcho of Solidworks about this. the stock answer is that you cannot represent new features in the older version, but that is hogwash, you just make those features, and ONLY those features that are not directly translatable dump to imported geometry. Solidworks knows this, but the intent is to force everyone to maintain a subscrlption service and to upgrade often. but the problem is that the bugs in new releases usually make the new release virtually unusable until sp 2 or so comes out. but then you have problems where one company or division upgrades but the others don't and suddently nobody with the older version can open any file that has been touched by the newer version (just opening an assembly wiill convert all the subassemblies and parts to the new version upon closing.). I have that problem now, one engineer at another location upgraded, forced the entire location to upgrade in order to work on his stuff, and now nobody at my location can open any of thier stuff.