587/607 are both pointless, because all of the predictions they used based on that date did not happen except in their own fevered imaginations. That the JWs have the wrong date is secondary to the fact that they made a prediction based on the wrong date-and even with the right date, the prediction was wrong. All the predictions LEADING from that date were wrong. Basically nothing to do with 1914 has been proven, all the interpretations about that date have changed when the predictions were proven to be wrong (generations etc). 1914, if you educate yourself well on it can be your secret weapon still.
I personally think that the WT stance on blood alone is provably false biblically and their consistency in its application is so false as to be laughable-except that it has proven so fatal. Those two things, if you educate yourself very fully on them, and focus strictly on them should show her what the religion is worth. Not much ethically or morally, though quite property rich. But isn't that just LIKE organized religion?