>>75937204He can read just the novels.
They're all pretty standalone with the exception of The Final Problem which kind of gets spoiled by the book that was released after it but it's VERY famous so I assume he already knows about the ending (he watched the 2nd RDJ movie recently too).
There are actually some famous characters like Irene Adler that are short-story only characters but they're like one-offs and aren't really important to the overall plot or anything.
