Was never a Truck person in the UK, but I love it Comfortable on long journeys, lots of toys, lost of space in the cab. Although if you take 4 people then a tonneau cover for the back is a must as luggage space is then restricted. The Bed is very useful for slinging stuff in
Servicing and parts are cheap, but how that equates to the UK as they are uncommon over there is a different matter.
Would not bother with the V10, yes it makes a nice noise, but you will see the fuel gauge go down while idling The Hemi is a excellent engine, and the 2013 Trucks are far more economical than previous Hemi's.
Along with the Tonneau, it also worth getting a bed liner for some protection.
They are however very big . . . so on the UK roads I can see that being a little challenging.
If your Dad has any questions let me know