Bruce Willis' Heartbreaking Diagnosis: Family Is 'Focused on All the Happy Moments They Are Able to Share'

Bruce Willis' loved ones are cherishing every memory together in the wake of his aphasia diagnosis.

The 67-year-old Die Hard actor's family revealed on social media last week that he is "stepping away from the career that has meant so much to him" after "experiencing some health issues," including a recent diagnosis with aphasia that is "impacting his cognitive abilities."

His wife Emma Heming Willis, with whom he shares two young daughters Mabel and Evelyn, and ex-wife Demi Moore plus their adult daughters Rumer, Scout and Tallulah all signed the message: "This is a really challenging time for our family and we are so appreciative of your continued love, compassion and support. We are moving through this as a strong family unit, and wanted to bring his fans in because we know how much he means to you, as you do to him."

For more on PEOPLE's cover story on Bruce Willis, listen below to our daily podcast PEOPLE Every Day.

A source tells PEOPLE in this week's cover story that Willis' loved ones are more grateful than ever for joyful family times, including celebrating Mabel's 10th birthday two days after announcing his retirement.

"Emma is especially grateful for the daughters she shares with Bruce," the source says. "Everyone is focused on all the happy moments they are able to share."

RELATED: Emma Heming Willis Thanks Fans 'from the Bottom of My Heart' Following Husband Bruce's Aphasia News

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According to Mayo Clinic, aphasia "is a condition that robs you of the ability to communicate. It can affect your ability to speak, write and understand language, both verbal and written." It can develop after a traumatic brain injury or can be an early sign of degenerative brain conditions, though Willis is not known to have suffered a brain injury.

The star's family is "doing whatever they can [to support him]," a source close to Willis says, adding, "They have rallied around him in a big way to help Bruce cope with what is to come."

RELATED GALLERY: Bruce Willis and Emma Heming Willis' Relationship Timeline

A source close to Emma, whom Willis wed in 2009, says, "As someone facing health challenges, Bruce couldn't be part of a better family. It's been shocking. And it's not easy seeing a spouse decline. But she's trying to keep it together for him."

As the couple put it in 2016 when talking to PEOPLE, they experienced love at first sight: "When we first met, I was surprised at how charming and how funny he was — and extremely handsome. That was my first thought of you," Emma said at the time. Willis added, "I was already in love with her."

For more about Bruce Willis and how those closest to him are showing support, pick up this week's issue of PEOPLE, on newsstands nationwide Friday.