I am looking for the quickest way to get him to speed.
The quickest way might be to give him the time it takes, although that could easily be a year or two.
Sure, it seems easy to teach him a simple language (C#, if he's to do .NET stuff), but learning a language is not learning to program.
If he never has programmed, then, besides the syntax and library of at least one language, he will have to learn about arrays, linked lists, the compilation model of whatever language he learns, modularization, resource management, paradigms, patterns, Big-O-notation... - the whole enchilada. That's a lot of stuff to plough through, and most of us took several years just to learn these basics, and even more to become a real professional programmer.
There's material out there that covers a lot of this (like Stroustrup's newest book that teaches programming using C++, rather than teaching the language C++), but there isn't very much of it and nothing that covers all of it. So the guy must be willing to learn, and to read a lot of books and articles.
As to how to do this: I don't have a full-blown curriculum at hand to paste here. (Sorry.)
What I'd recommend, though, is to start with teaching him one programming language, so that he has a chance to make some fast initial progress and get some encouraging results. There's quite a few books out there to teach such languages, pick one you're familiar with. If the book has many exercises, and he is willing to do them, be prepared for spending a lot of time helping him with those. If the book doesn't have (m)any, start to think up your own ones well ahead, but be prepared to adapt them to his level/speed of understanding.
If that first language wasn't either C or C++, IMO he should learn one of these next. K&R is good for that, as is Stroustrup's TCPL or, if he can (with your help) deal with a steep learning curve, Koenig/Moo. The reason I'd recommend this is that, once you know C or (IMO preferably) C++, it's relatively easy to pick up any of those C derivates like C#, Java, ObjC...
For the rest, provide him with a constant stream of good books and articles. I don't think it's very helpful if we suggest too many of those, since 1) it has to fit to your company's culture, and 2) you have to feel comfortable telling him to learn that stuff.