Primary should last about 2 weeks, then rack and let sit for another month or 2, when it's all but clear, and there's a good bit of sediment in the secondary, go ahead and rack again. Another couple weeks in tertiary (or bulk aging for a couple months, if you wish), will make sure it comes out crystal clear (mind you, that also depends on the recipe).
If it's too yeasty, it's because he bottled too soon, make sure it's perfectly clear before you bottle, and you shouldn't have any problems.
And yes, if after you bottle it, you think it's too dry, just add a little splenda to the bottom of a glass before you pour the cider in. I personally use one packet of splenda per 750ml bottle of Apfelwein, and it comes out damn near perfect. My New England hard cider is almost to the bulk aging stage, so I don't know how that will come out (5 gallons fresh pressed cider, 1 packet Cote De Blancs, no extra sugar or spices).