It would be ridiculous to cancel the storyline because a group of mothers can't handle it. Sure it's pretty grim, but no one's saying her actions are typical of everyone in that situation especially if you take into account the character's context and the previous deaths she's already faced. I can think of one soap storyline that was a bit close to home but I didn't pick up arms and cry for the storyline to be cancelled and I don't see why those people should. I can understand the producers deciding to cancel a storyline because of its similarity to real life events for example, changing the Lucas prostitute storyline because of the prostitute murders and changing a child abduction storyline because of Maddie McCann (probably a different soap?) but this would be too far.
A simple answer would be to tell them not to watch it or to remind them that no one's saying her actions are typical of mother's in her situation but anymore would be ridiculous and reactionary.
I've tried to be as cryptic as possible because it's a discussion about the link rather than the storyline.