CNN  — 

A Parkland school shooting survivor is calling for Melania Trump to fulfill her pledge to combat cyberbullying – starting with her own family.

“Hey @FLOTUS you say that your mission as First Lady is to stop cyber bullying,” 14-year-old Lauren Hogg tweeted Friday. “Well then, don’t you think it would have been smart to have a convo with your step-son @DonaldJTrumpJr before he liked a post about a false conspiracy theory which in turn put a target on my back.”

President Donald Trump’s eldest son liked a tweet promoting a false conspiracy theory that claimed that Lauren Hogg’s older brother, David, had been coached by his father – a former FBI agent – to speak out against President Donald Trump.

“The fact that Donald Trump Jr. liked that post is disgusting to me,” David Hogg said on “Anderson Cooper 360” Wednesday.

In her tweets, Lauren Hogg said that Trump Jr.’s seemingly tacit endorsement of the conspiracy theory had “created a safe space for people all over the world to call me and my family horrific things that constantly re-victimizes us and our community.”

The teenagers’ mother, Rebecca Boldrick, told The Washington Post that her family has received death threats online due to the conspiracy theories.

“Even though I thought it couldn’t get worse it has because of your family,” Lauren Hogg wrote to the first lady.

Melania Trump has said she wants to use her platform to tackle issues facing children, including bullying. She has addressed the issue on several occasions.

“We must teach each child the values of empathy, communication – a core of mindfulness, integrity and leadership, which can only be taught by example,” the first lady said at a United Nations luncheon in September. She made a surprise trip to Michigan in October to discuss the problem with middle schoolers there.

Many have pointed out the ostensible irony of the first lady promoting anti-bullying given her husband’s combative and sometimes belittling rhetoric. However, asked by CNN in October if the first lady feels the need to reconcile that irony with what she’s trying to accomplish, Melania Trump’s communications director Stephanie Grisham said flatly, “no.”

CNN’s Kate Bennett, Nicole Chavez and Betsy Klein contributed to this report.