Casey Davidson/Instagram Casey (L) and Pete Davidson with their dad, Scott Davidson
The Saturday Night Live alum's younger sibling shared a tribute to Scott Davidson, a New York City firefighter who died in the 2001 terrorist attacks, on Sunday, 9/11's 21st anniversary.
"This year more then ever I wish you could be here. We miss you, we celebrate you and we remember you every day. Proud to be your caseygirl 💜" she wrote in a post, alongside a trio of images of the family's late patriarch.
In the first photo, Scott wears his New York City Fire Department uniform and sunglasses and smiles from a rooftop, while in the second, he holds a toddler-age Casey.
Pete, now 28, is pictured in the third photo as a child, wearing his father's firefighter gear and smiling broadly while Scott buttons up the jacket.
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Scott died when his son was just 7 years old, and on the anniversary of his dad's death, Pete often posts on social media to honor him.
Since his recent Instagram purge, Davidson hasn't said anything on social media about losing Scott 21 years ago, but he has shared special memories of his dad in the past.
In 2015, the actor shared a series of tweets remembering his father, laced with jokes and appreciation to friends who reached out on the day, writing, "I really appreciate it. I'm a very lucky guy."
He also ended the day on a serious note, tweeting, "All jokes aside. There's not a day that goes by where I dont think of u. Ur my hero. Cant wait to see u again someday."
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Davidson revealed that he's been thinking about being a dad since he was a kid.
"Since my dad died, I was like, 'Oh, I can't wait to have a kid,' " The King of Staten Island actor said, noting how he once felt like fatherhood might not be his path.
"I don't like saying corny s—; the reasoning was, like, I don't want a kid to ever feel like how I feel right now," he explained. "It wasn't [my dad's] fault; he passed away. But just to be there so that someone doesn't have to feel like that."
When it comes to having children himself, Davidson said, "I'm very excited to do that for someone and watch them have what I didn't."