Britney Spears Gets Post-Rehab Time With Kids, Kevin
03/23/2007 AT 04:00 PM EDT
"She's is going to lay low," a friend says. "She's taking care of herself."
In the days since Spears checked out of Malibu's Promises treatment center, Federline and their sons Sean Preston, 1, and Jayden James, 6 months, visited the singer once, and the children came with a nanny another time.
Federline, who cared for the boys during the four weeks Spears was at Promises, hopes to continue doing so until he believes her rehab follow-through is working, a source told PEOPLE on Wednesday.
Meanwhile, he's planning to go to Las Vegas this weekend to celebrate his 29th birthday at Caesars Palace's Pure Nightclub, returning three weeks after a visit there with the kids while Spears was in rehab. Spears is not expected at the party.
Before her stint in Promises, Spears was working on a new album for release this year. R&B star Ne-Yo had been slated to work with her, but he tells PEOPLE: "The Britney stuff is on the back burner right now because Britney is fighting her battles and dealing with her demons. I really think if people leave Britney alone for a minute that she'll be alright."
Still, he says, he has heard some of her new songs and "musically she definitely has a chance to come back."
"Now she's got to do what Whitney did," he says. "She has to take the time to get the negativity out of her life so that she can come back and do what people love her for in the first place."