By Michelle Tauber
April 20, 2009 12:00 PM

They are a couple who adore nothing more than gathering loved ones together for a celebration, and not so long ago, John Travolta and Kelly Preston had an especially festive spring to look forward to. Their daughter Ella Bleu would be turning 9 on April 3; son Jett would mark his 17th birthday on April 13 and patriarch John would be preparing to promote the June release of his big summer thriller The Taking of Pelham 123. All that was before Jan. 2, when Jett died suddenly from a seizure disorder during a family vacation. Now his parents simply try to carry on. A few days ago they held a birthday party for Ella, “just as they would any other year,” says a close friend. But for the most part the once gregarious Travoltas have kept quietly to themselves. “They are living their lives as best as possible but keeping their profile low,” says the friend. “They are still struggling, and each day is a challenge.”

Clearly they are in no rush to resume their once high-profile lives. Neither John, 55, nor Kelly, 46, has made any public appearances since losing their “sweet Jetty boy,” a loving son whose developmental delays and physical challenges were never discussed by his parents. Still reeling, John, who is widely regarded as one of Hollywood’s most press-friendly stars, has yet to commit to any kind of publicity for Pelham. Meanwhile the couple’s friends and colleagues are taking their cues from the family as to when—or if—they’ll be ready to step back into the spotlight. “John is a strong man, but we want to leave him in peace,” says Olivia Newton-John, a longtime pal. “To lose a loved one—it’s the worst time in anyone’s life.”

Slowly, however, John and Kelly have begun letting the world back in—starting by reaching out to those closest to them. “They are grieving just like anyone else,” says a family friend who saw them recently. Although they seldom leave their Florida compound, “they aren’t secluding themselves or paralyzed. [Seeing them] was like old times. Nothing awkward and no topics to dance around. There were smiles.”

A smile is a significant milestone for a devastated family who had “set up their whole life around [Jett],” as a friend, actress Anne Archer, told PEOPLE after Jett’s death. And they have withdrawn: John and Kelly have been spotted only a few times outside their estate in the fly-in community of Jumbolair in Ocala, Fla., since their son’s Jan. 8 funeral. A few days after the service, “John looked so beaten down,” says a source. “He’s usually very confident when he walks around Jumbolair, smiling and waving. This time, his head was down, his shoulders droopy. You didn’t have to talk to him to see that he was grieving.”

Folks at the family’s regular haunts in Ocala—including a Denny’s where they often dined in the wee hours (John is a notorious night owl) and the nearby mall where they liked to stroll—say John, Kelly and Ella have been almost completely absent since Jett’s death. During a rare February shopping trip at a local Macy’s, Kelly “seemed extremely sad,” says a source. “She had a gentle and kind spirit about her. But you can definitely feel an aura of sadness. You can feel it coming out of her pores.”

Still, friends say the family—who have recently spent time in L.A., where they also have a home—continue to draw strength from each other and from their strong Scientology beliefs (see box). “They’re relying on their faith to get them through this,” says another family friend. “Their faith is solid, and their family is solid.” Adds their pal, actress Leah Remini: “How do you deal with the greatest tragedy in your life? I can tell you that they are handling it the best any parent could ever deal.”

Making the grieving process even more difficult is the ongoing extortion investigation in the Bahamas, where Jett died at the family’s villa at the Old Bahama Bay resort after being discovered in a bathroom. In the weeks that followed, local prosecutors charged a paramedic and a former Bahamian senator with allegedly attempting to extort $25 million from the Travoltas via threats. Both have pleaded not guilty. Although the case is scheduled to reconvene April 16–and John may be called to testify—the trial “is small potatoes compared to losing your beloved son,” says one friend.

Grateful for the widespread support they have received—John and Kelly wrote thank-you notes to many who have helped them during the tough past few months, expressing their appreciation for the “inherent goodness in the human spirit”—the couple are “moving on little by little,” says a source close to them. “Ella is grieving too, but they are all trying to move on as best they can.” Of course Jett—whose 17th birthday would have no doubt inspired much joyful celebration—is always in their hearts. “They’re celebrating the good things about Jett’s life,” says a family friend. “They’re going to survive this. They’re a strong family.”