To me, the whole point of reading imaginative fiction like Dahl’s work is that it transports you to some other place. A different world with different people in it. The author created that whole world with language, and you’re getting it through just words on a page—that has always seemed to be part of the magic to me.
I think we ought to respect that, and treat suggestions to “improve” old literature by “updating” the language with the same mild derision that’s useful on those loons that wanted to paint over the cigarettes in old movies