User blog comment:FairyRaven/Fairy Tail Chapter 467: Mother's Key, Review and Commentary/@comment-24039234-20160104121942/@comment-7418318-20160106195937

Or that manipulator didn't know that Layla died and considered Layla a threat. It doesn't necessarily have to be about Lucy herself. That Brandish would want to kill Layla's daughter as a substitute might be an unforeseen side-effect of the original (now obsolete) plan.