Unless its an 04+ reg cab, I dont think the new Type R's are going to fit...unless he's really short.
We had an AA Atlas in my buddies 97 reg cab (would be the same from 97-03) with a 6.5 inch mounting depth-I think that is all the deeper of a sub you would want to go...
i had a 12'' type r in my 2001 f150 . I had the box in the middle behind the seats with the sub right behind the console that was the only way to fit it , no way for 2 of them
crap, hes a good 6' atleast but he told me he had 13" toward the bottom and 8 around the mid section of the seat and back wall....we'll see gonna go over next sunday to do the build...