Not kidding, I am asking seriously-. Is there any recorded handwritten note by him that proves that he even can handwrite?
Because this is his signature. Scribbled curls like a spiral cable.
With big imagination I could read a capital "J" into it at the beginning, and later a very strange way of painting an "o". And that is all letters one could attach to it even if being utmost well-meaning.
Could it be that he is illiterate and has hidden it successfully for this long?