If you plan to use a flat bar, why not try the Campagnolo Flatbar Ergo Shifters. They look great. Anyone have an opportunity to test any of those at the trade shows? You could then run a nice Campy drive train on that ti frame you plan to get your dad.
Personally, I would not limit your dad's hand position by going with a flat bar. Stick to the standard road bar and install cross levers on the flat portion of the drop bar.
Brakes: You can only use V-brakes on a frame that has brake bosses. The bosses are the same for both V-brakes and cantilever brakes. V-brakes on a cross bike are heavier and usually require the added Travel Agent adapter if you use a road shifters. There are some beautifu low profile cantis being made now that have plenty of stopping power for what your father might be doing. take a look at Empella, Spooky and Paul's canti brakes. None of those canti brakes require a Travel Agent adapter to use with a road shifter.
If you go with a road drop bar you can install the cross levers mentioned above. Look at levers offered by Empella, Paul, IRD and Salsa.
Tires are tricky. If your dad plans to be mostly on paved road, but dabble on some fire roads/paths, then I would recommend a tough training tire for the road. Check out the training tires from Specialized. They are not WW light, but they are very durable, roll well and come in wider widths for extra comfort and stability. Alternatively, for more path oriented riding, you could run some of the low profile cross tires from Ritchey (Speedmax Cross comes in 700X30, but rides like a 28). There is also the diamond tread tubular clinchers from Tufo (Special Diamond 700x28) - these are fantastic.
If your dad is not planning to do super steep routes, then you could save some weight and run a compact crankset with a high ratio cassette (13-26, 13-28)
Good luck with the build. Send in a photo of the final product.