Though her father, attorney Robert Kardashian, passed away in 2003, Kim Kardashian
says her nearly 2-year-old nephew Mason
serves as a constant reminder of him.
"When I look at Mason he's so much like my dad," Kardashian, 30, told PEOPLE at Monday's Angel Ball to benefit Gabrielle's Angel Foundation in Manhattan. "He gives these facial expressions sometimes that look just like my dad."
"My dad would have loved him," the reality star added.
Robert Kardashian died at age 59, only eight weeks after being diagnosed with esophageal cancer.
Kim, who was 22 at the time, said speaking at her father's funeral was "probably the hardest thing I've ever had to do in life."
And now, eight years later, the newlywed
says it's equally difficult not having her father around to share special moments in her life.
Kim said her father "would have loved" her husband, basketball player Kris Humphries
"That's really hard ... that he'll never get to meet my husband or my children
, she said.
In her speech at the event, which was sponsored by jewelry designer Lorraine Schwartz, Kardashian spoke of her father's experience with his illness.
"I wish we knew a little more about the disease," she said. "My dad didn't really want to tell anyone he was sick. He wouldn't even tell his parents he was sick. He didn't tell them until like a week before he passed away. He was the kind of guy [who] never wanted to go to the doctor to see what was wrong, because he hated doctors – sorry, doctors out there."