Cannondale are very well regarded manufacturers of aluminium frames. Tiagra is a solid groupset etc. Cannondale bikes are usually a bit more costly than other brands, i.e. for the price you get a Cannondale alu bike with tiagra, you can likely get an alu bike with 105 from other brands like Trek etc, but you are paying for the name, supposedly the quality and expertise that Cannondale have in aluminium frames comes with it. It should have a lifetime warranty and depending on the period in which is was made, possibly also handmade in the USA (some people like that, even if it doesnt neccessarily mean that its a better bike than a mass manufactured one from the east). He should definatelly ride it 1st if possible, because CAAD frames have a reputation for stiffness and raceyness, not comfort
If he is over 6ft, he will likely need a 58cm-60cm frame. I have a CAAD9 and being around 6'2" to 6'3" and ride a 58cm frame.