In my experience with work trucks, the Dodges are made out of the same plastic as Rubbermaid containers and the only good reason to buy a Dodge is to get a Cummins.
The GM half tons have good value in them, but the front end parts seem to wear out fast and pick up weird electrical glitches over time. They are nice in half tons and performance for dollars pretty good, but if you can get a better deal I'd take the better deal. Half ton extended cab with a 4.8 would be a nice ride. One thing I like, especially with the half-ton GM crew cabs is they have the step in height of a car.
I'd probably get a Ford though if the deals on them are that good. 4.6 is a good little motor (16 year old kids don't need horsepower), the trucks are pretty solid all-arounders (my dad has ran three to 75,000 miles or more the past three years, the most recent one made it to 87,000 miles of hard off road, heavy use and didn't need any major work.) Extended cab with a six and a half foot box, two wheel drive, 3.55 limited slip rear end so it makes alright mileage and the 4.6 motor would be a good combination for him if the price is right, I think.
Extended cab would be better than crew cab so he has the extra cab space/jump seat room but that way he won't have five friends with him distracting him all of the time. Not saying it's wrong to give your kid a brand new, high horsepower crew cab truck, but if he doesn't need those things keep him out of trouble.
I'd personally look for a two year, low mile lease return, not eat any of the depreciation and he'll probably be just as happy with it as something brand new. My first car was a decade old when I got it and not in the greatest shape but [censored] was I happy to have wheels.