[deacsoft]

There are a ton of limit hold'em books available. Obviously, some are better than others but there are a number of them that offer something useful. Even if the book, as a whole, is inferior to another title there might be a small gem of information that he cld find to be very useful. I think HPFAP would be a great book for him to read.
The Theory of Poker by Sklansky will provide him all the "nuts and bolts" type information he needs to excel.
Real Poker II, The Play of Hands by Cooke is a little more "user friendly" than the 2+2 titles and provides some great perspective on how to play hands out.
Middle Limit Hold'em by Ciaffone and Brier is another solid strategy book that may be more applicable to the limits he plays.
I think any of the above would be good purchases and would help him considerably. However, it's best not to over load him with information. I'd maybe start him off with two and go from there. If forced to pick just two I'd choose HPFAP and TOP.