As actor Bruce Willis approaches his 69th birthday, his heartbroken family and friends are bracing themselves for what could be an emotional goodbye. The Hollywood icon, who was diagnosed with frontotemporal dementia (FTD) last year, has seen his health rapidly decline, leaving his loved ones fearing that this birthday may be his last.

"Bruce's disease has progressed quickly, and he can't really communicate anymore," says a source, adding that the actor's wife, Emma Heming, his five daughters, and his ex-wife Demi Moore are planning to gather to celebrate him while other friends have been rushing to spend time with him before it's too late, as reported by In Touch. "Those who love Bruce want to cherish every last moment with him. They all realize this could be his last birthday."

The family's mixed feelings were evident in the heartfelt messages shared on Bruce's birthday last year, just a month after they announced his FTD diagnosis. His daughter Scout posted on Instagram, "Today is not necessarily an easy day, because it's a day full of so deep love, and our grief really does show us the depth of our loving for someone." Emma Heming added that she "started the morning by crying" and admitted that looking at videos for a tribute montage was "like a knife in my heart."

Recent developments in Bruce's condition have heightened the family's concerns. "Recently, he's lost his appetite and can't stop losing weight," says an insider, explaining that this can be an indication that his disease has progressed to the end stage. "According to family members, the challenge at home is making sure that he's getting enough to eat, that he's not skipping mealtime, and that his diet is filled with foods that have the chance to improve his health instead of subtract from it."

The disease has already robbed Bruce of many of his abilities. "He's not totally verbal; he used to be a voracious reader he didn't want anyone to know that and he's not reading now. All those language skills are no longer available to him," revealed his old friend, Moonlighting creator Glenn Gordon Caron, in October. The situation has worsened since then, with the source adding, "He can't communicate anymore, and he has difficulty recognizing people."

Despite the challenges, Bruce's family has learned to appreciate every moment they have with him. "Given the givens, he's doing well. What I'll say is what I say to my children, which is it's important to just meet them where they're at and not hold on to what isn't," Demi Moore, 61, said of Bruce's condition on Good Morning America on Jan. 31. "Because there's great beauty and sweetness and loving and joy out of that."

Bruce's daughters are doing their best to preserve memories and maintain a connection with their father. "They're taking as many photos and videos as possible," says the source, adding that Rumer, 35, Scout, 32, and Tallulah, 30, "love to sing, which is something Bruce often did with them. Even now, they will sing to him and play music for him, because that was always a passion of his. It perks him up and helps connect them to him."

For Emma Heming, who has made it her mission to raise awareness for FTD and the importance of mental health for primary caretakers, this is an especially rough time. "She continues to be the best person on the planet to look after Bruce, protecting him from the everyday hazards that can be dangerous for somebody with his illness," the insider says. The couple's 15th anniversary, which falls about a week after Bruce's birthday, is a poignant reminder of the life they once shared.

The ordeal has brought the family closer together, with Demi Moore playing a supportive role despite being Bruce's ex-wife. "Despite the fact that she's the ex-wife, they've always gotten along well, and Emma appreciates that Demi is involved in a respectful way," says the source, noting that the actress, who was married to Bruce for 13 years, is planning a "touching tribute" for his birthday.

As Bruce's loved ones come together to celebrate his life and legacy, they remain hopeful for his future. "Everybody's staying positive about Bruce's future and hopeful that he finds some kind of comfortable plateau or even, God willing, shows signs of improvement," says the insider. Above all, they are determined to surround him with love and happiness for as long as possible. "No matter how much time Bruce has left, they want him to be surrounded by love and happiness," says the source, emphasizing the importance of cherishing every moment they have with the beloved actor.