"She must be going through a hard time," Audrina Patridge says of mourning Montag
Credit: Karl Larsen/INF; Fitzroy Barrett/Landov

While Heidi Montag mourns the loss of her stepbrother, several of her Hills costars have reached out to offer their condolences.

“I actually texted her,” Audrina Patridge told PEOPLE at Thursday’s Sleepwalking premiere in West Hollywood. “It was really sad. She must be going through a hard time.”

With Montag in Colorado to attend the funeral for stepbrother Eric O’Hara – a veteran of several combat missions in Iraq and Afghanistan who died in a freak accident Feb. 28 – Patridge noted, “I haven’t seen her.”

Although Patridge didn’t hear back from Montag, she added that costar Whitney Port “called her too. Hopefully she’ll be okay.”

Patridge, 22 – who spent time on MTV’s The Hills hanging with Montag before the blonde’s friendship with Lauren Conrad imploded last season – noted that Montag often mentioned her 24-year-old stepbrother.

“I always used to hear her talk about him,” she said. “So I knew of him. But I never knew him.”

For now, Patridge and her Hills crew are wrapping up episodes for the third season – and preparing for the next one.

“It’s just all of us getting to know each other even more than we did,” she said, adding that it results in, “the typical drama that everyone loves to watch!”

Asked if Conrad, 21, and Montag will reconcile, Patridge teased, “We haven’t started fourth season yet, so you never know what could happen.”