All of their efforts so far have been a bust, as things are still on an Iris-dies-a-bloody-Savitar-death track.
Well, at this point, it’s really not a surprise that Barry is looking for help in (possibly) all the wrong places.
He and his team have already tried a wide variety of things to stop this horrible version of the near future from coming to pass.
So, if Barry thinks that a bad guy he battled in the past can help stop this, it makes total sense that he’d be willing to try pretty much anything now.