"Brooke has recently moved to a new rehab facility in the Los Angeles area. She wants privacy and to be away from cameras that were bothering her at the other place," a source close to Mueller, 32, tells PEOPLE.
"She is doing well and can come and go and play with the kids in the park if she stays in Los Angeles. She wants to keep it together for her twins."
The source adds: "Brooke and Charlie are getting along okay, and he supports her stay in rehab."
Separately, Sheen's rep, Stan Rosenfield, confirmed that L.A.'s Department of Children and Family Services paid a "routine, procedural" visit to Sheen's house on Sunday to check on 11-month-old twins Max and Bob.
The visit was made at the request of the Pitkin County Department of Social Services in Colorado, which is investigating Sheen and Mueller's Christmas Day fight in Aspen.
Meanwhile, a friend of Sheen's says the actor, 44, was able to spend more time with the kids last week while Two and a Half Men was on hiatus. "Charlie's been at home, being a full-time dad," the friend says. "The boys are doing great."
With reporting by LINDA MARX