On the show, Ashlee said that after learning of their father's prostate cancer diagnosis, she and the family were devastated, but Jessica was the one who was closest to Papa Joe.
"Jessica was more of a daddy's girl and I was a mommy's girl," Ashlee admitted.
Explaining how frightened they all were about Joe's health, Ashlee said she even took desperate measures to be more like Jessica.
"I've been developing and growing my relationship with my father," Ashlee said.
During an emotional meeting, Joe told his daughters how precarious his situation was.
"The biggest part is, because I don't have testosterone, I just don't have energy," he said. "So you have to power through."
"A year ago changed my life. I remember saying to my doctor, 'What if I don't have surgery?' He said: 'In six months you'll be dead.' I really wrestled with saying I'll see you guys later. I couldn't do that to you and to your sister and to my grandbabies," he tearfully told Ashlee.
"I have a different appreciation for you than I did when I was a kid, a stubborn kid," she told him. "I'm so lucky to have you, daddy."
Sadly, Ashlee's father was not the only one suffering a health crisis.
Evan's brother, Ross Naess, suggested they go climbing together to honor their father.
"I haven't climbed since dad, man," Evan told his older brother. "I'm not trying to get on a mountain right now."
But eventually, he changed his mind.
"I feel like one of the biggest things I got from my father growing up was, 'You can face certain fears,' and no matter what, I can push through," he explained.
Evan Ross then explained how their dad's death affected him.
"You wanna make sure you remember everything. You don't want it to become a distant memory," he sadly confessed: "I would've liked him to have met my wife and my daughter…he was good with women and he was special."
He even poured his emotions into a new song, which brought his wife to tears.
"I love you," a crying Ashlee Simpson told her husband. "That, like got me. You like really got me. I know how proud your dad is of you."
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