Hill and Lansendel both understand Shaer quite well, and it's not surprising that the Lady of the Night would turn her gaze to other worlds.
But they also know what Shaer means; although her primary goal is still world destruction, now she won't indulge in pointless activities to dissipate her rage.
However, she won't do nothing at all.
Compared to before, she will first see if there is any external world that can aid her in achieving her ultimate goal.
William indeed won't help her, but he also won't hinder her.
That's exactly what Lansendel wanted to ask about... but the God of Justice, who resolutely refuses to set foot in Toril, has chosen to bury his head in Teraxil, ignoring the storm brewing outside.
In other words, unless it affects Teraxil, William surely won't restrain Shaer's malevolent actions.
