Spears hands mother Lynne papers on June 28
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's mother is "brokenhearted" over recent difficulties in her relationship with her famous daughter, a friend of the family tells PEOPLE.
Lynne Spears "has cried her heart out over the trouble between her and Britney," says the Spears family pal. "She is brokenhearted. She wants her baby to be okay and to bring her grandkids home to Kentwood and raise them in a normal environment."
On Thursday photos showed the pop star handing papers to her mother outside a trailer in Valencia, Calif., then walking away as her mom sat on the trailer steps, shocked.
Although one report identified the papers as a restraining order, TMZ.com
reports that Spears actually handed her mother a letter from an out-of-state lawyer.
According to TMZ, the letter asks that Lynne stay away from Spears's sons Sean Preston, 1, and Jayden James, 9 months, if she is taking any medications that might cause her to be impaired.
Later, when asked by photo agency X17
what the papers were, Lynne joked, "It's a love letter." She ultimately clarified: "She did not serve me."
As for what may be behind the rift between mother and daughter, the family friend tells PEOPLE: "I think Britney is angry that her family got involved in getting her into rehab."
In February, Spears checked into Promises Treatment Center in
Spears handed her mother the document on the set where her
sister Jamie Lynn, 16, was filming her Nickelodeon show Zoey 101.
The New York Post
reports that Spears learned her mother's whereabouts from the paparazzi camped outside her
Beverly Hills home. Spears then drove to Valencia with her sons in tow, according to the newspaper.
In other Spears news, a source close to her ex, Kevin Federline
, told PEOPLE Thursday that Federline has resisted signing divorce papers
out of concern over Spears's post-rehab partying.