Kevin Federline visited his estranged wife, Britney Spears, in rehab on Friday, PEOPLE has learned.
Spears, 25, is currently being treated
at Promises in Malibu. A source familiar with the situation says Federline, 28, has been involved in her stay there. "He cares a lot about her," the source said.
Federline stopped by the facility on Friday and stayed about an hour and a half.
On Thursday, Spears's father, Jamie Spears, 54, told FOX News
from his home in Louisiana that his daughter is "a sick little girl. ... We're just trying to take care of her."
He added that his daughter's problems are "not about what other people think" and that he and Spears's mom, Lynne, are "concerned about our daughter."
However, reports that Spears is on "suicide watch" are false, her manager Larry Rudolph told Extra
"The story is absolutely untrue. She is in rehab, and it is very disappointing that various media outlets are running these false stories about her, as Britney tries to get better," Rudolph said.
Meanwhile, Federline is anxious about his wife's condition – and about the couple's two sons.
"Britney scared everyone pretty bad. Kevin is worried that's for sure," a source close to Federline tells PEOPLE. "Kevin just wants her to be OK. He loves her, so however she can get better is just what we'll have to accept. [They] will make it work with the kids – it's all still for them."
One person who agrees that Federline has Spears's best interests at heart is her childhood friend and first husband, Jason Alexander, whom the pop star wed in Las Vegas in 2004 (their marriage was annulled 55 hours later).
Federline is "a good dude," Alexander, 25, told PEOPLE on Tuesday, the day before Spears checked out of
the Promises rehab center after a one-day stay. "I know he takes care of those kids."
Alexander, who in November called Federline "an idiot,"
now thinks Spears's estranged husband "just got caught up and manipulated," he says. "Maybe getting Kevin out of her life wasn't the best thing for her."
With reporting by LYCIA NAFF, MARK LAMBERT and JENNIFER GARCIA