having the equipment do'nt mean he can use it. no offense but i have been playing about with DSLR's for around 8 years, spent thousands of pounds on lenses, does that make me an expert ???
a camera spacific guide would be an excellent gift. as its not a manual as such as a manual just tells you what stuff does. those guides tell you how to get the best possible out of that spacific camera
if he has a nikon, he is likely to stay loyal to the nikon brand.. if he changes his camera, just buy the other model guid for his next birthday etc