There is, to put it lightly, considerable legal argument over who owns a created language or lettering system. This is an extremely interesting question.
I have written elsewhere about my love/hate relationship with Christopher Tolkien, for reasons just such as this -- he has a very, very anachronistic sense of the world. When it comes to editing something like the Legend of Sigurd and Gudrun, it comes in handy. But applied to the mutation of his father's work into a multimillion dollar media empire, his perspective is disastrous and tone deaf.