Your right, he and his family are going to look pretty foolish if they claim him to be DT, and have Woodward turn around after his death and deny it.
Woodward will never release the information as to expose DT (if he/she truly is an amalgamation) would discredit some of their investigation.* Then he would have to account for who exactly said what. Who knows what he did with the notes?
*Note that the leaks were probably true, but that the issue would be how he would be able to back them up if the premise that one person leaked it were not true after all.