Bruce Willis was diagnosed with dementia in 2022.
In a post on Instagram Monday, the actress, 35, shared with her 1.1 million followers that she is "missing" her dad as his condition continues to worsen.
"Really missing my papa today. 🥲," Rumer wrote in a caption on the social media platform.
For the photo, she attached a picture of herself and her father, 68, from when she was a baby. In the pic, Bruce is holding his young daughter in his arms as he looks at her fondly.
Some commenters immediately expressed concern that the Hollywood icon had passed away, however, many seemed to make the connection to his dementia diagnosis, which causes a person to lose their memory, language and other functional abilities, according to the Alzheimer's Association.
Bruce was diagnosed with the disorder last year, and as a byproduct, aphasia, a brain-mediated inability to speak or to understand speech. According to the Mayo Clinic, frontotemporal dementia "is an umbrella term for a group of brain disorders that primarily affect the frontal and temporal lobes of the brain."
"Hugs. It’s an odd kind of hard to miss someone who is still here. Dementia is a cruel beast," one person responded to Rumer's post.
"Anticipatory grief is so difficult to process at times. I’m sorry," another responded.
"With dementia, grief begins so much earlier and lasts longer because you start grieving the loss before they are physically gone," a third person wrote.
The post from the Die Hard star's daughter comes just days after Bruce's wife, Emma Heming Willis, penned a heartbreaking tribute to her husband as he fights frontotemporal dementia.
In a personal essay written for Maria Shriver's Sunday Paper, the mother of two shares her perspective and what she's learned as she and Bruce's family navigate his disorder. In her step-by-step guide, Emma shares the value of community, being aware, and research.
"I struggle with guilt, knowing that I have resources that others don't," she writes. "When I’m able to get out for a hike to clear my head, it's not lost on me that not all care partners can do that. When what I share about our family’s journey gets press attention, I know that there are many thousands of untold, unheard stories, each of them deserving of compassion and concern. At the same time, I see that what I share matters to others who may be struggling, and in a small way makes them feel seen and understood."
Meanwhile, in early November, Bruce's daughter Tallulah Willis was a guest on The Drew Barrymore Show, and gave an update on her father's condition and what life has been like.
"He is the same, which I think in this regard I’ve learned is the best thing you can ask for," she said of her dad. "I see love when I’m with him, and it’s my dad and he loves me, which is really special."