The way you describe it, all suicides essentially become murders then, (no I'm not defending this piece of filth's actions) as anyone who does this has some reason, caused by some thing, action, person, wording, whatever that drove them to it.
Person goes to casino, loses all their money, comes home, kills themselves... The casino is guilty of murder for taking their money.
Person goes to church, confesses to something terrible, the priest tells them they are worthless pieces of filth because they did x, person goes home, kills themselves, the priest is a murderer.
Yes, what the person did was abhorrent. But they did NOT kill the other person. They mentally / verbally (or is that textually) abused them.
Drill sergeants bring people down, make them feel worthless, lower than the worm that eats dog shit all day, every day, and yes, some soldier wannabes end up suiciding, yet the drill instructors aren't charged with murder, even though they drove the recruit to it.
Do I think this person should get off scott free? No. Do I think they should be charged with murder? No. Accessory to murder (where the person who killed themselves is the murderer and murderee both) - possibly. Child abuse, reckless endangerment, verbal and mental abuse... absolutely...
Where do you draw the line, where do we stop? I don't have a good answer. Personally, (based on emotional response) I want this woman dead, preferably through the most painful and longest lasting method possible. Is that the right way to think? probably not...
Just some thoughts...