On Easter Sunday, a video surfaced of Chyna getting involved in an alleged public altercation at Six Flags Magic Mountain in which she was seen grabbing a pink stroller shaped like a miniature car and swinging it around wildly. The mother of two shares a 16-month-old daughter, Dream, with Kardashian, and a 5-year-old son, King Cairo, with ex Tyga. (Neither of her children were in the stroller at the time or appeared in the video.)
“Rob got very angry when he heard what happened at Six Flags,” a source tells PEOPLE. “He’s definitely worried about Dream when he’s not with her. He knows who Chyna is and he doesn’t like her behavior around Dream.”
According to the source, Kardashian, 31, is “happy” that the incident was captured on camera, as he most likely wouldn’t have found out about it otherwise.
“What concerns him, though, is all the stuff that he suspects is going on, but can’t confirm,” the source says.
- Want to keep up on the latest from PEOPLE? Sign up for our daily newsletter to get our best stories of the day delivered straight to your inbox.
The source also notes that Kardashian “thinks Chyna is wrong to bring new boyfriends around Dream.” She’s currently dating an 18-year-old hip hop artist who goes by the moniker YBN Almighty Jay.
“Rob can’t stand it and will try to have things changed by the court,” says the insider. After a contentious back-and-forth, the couple agreed to share joint custody of Dream in September.
After the video surfaced, Chyna posted a message alluding to the incident on her Instagram story, suggesting that she acted out in response to a fellow park patron trying to touch one of her kids. A representative for Six Flags confirmed a “verbal and physical” altercation had occurred and that both perpetrators were removed from the park.
“Being famous is hard enough dealing with scrutiny but when someone feels comfortable to come and touch your child it’s a whole other story,” she said. “I do not condone violence nor am I a violent person but shout out to all of the amazing mothers out there that will protect their children at all cost. Love, King and Dreams mommy.”
On Monday, a source told PEOPLE Kardashian and his famous family are focused on baby Dream’s wellbeing.
“The family is just relieved Rob isn’t involved with [Chyna] anymore,” said the insider. “Their biggest concern is that Dream is safe.”
RELATED VIDEO: Blac Chyna Says She’ll Protect Kids ‘At All Costs’ After Fight Video Shows Her Swinging Stroller
Kardashian and Chyna split over a year ago after a contentious and volatile relationship. In recent months, the father of one has distanced himself from his ex, who had an infamously difficult relationship with his family — largely stemming from the fact that Kardashian’s sister Kylie Jenner used to date Tyga.
“As soon as he realized his family was right about Chyna and removed himself from all the drama, Rob started doing much better,” a source recently told PEOPLE. “He is on good terms with the family again and everyone is happy about it.”
“He’s focused on what he should be focused on: Dream and his health,” added the source. “He wants to stay healthy for his daughter’s sake. He wants to be the best dad possible.”