"The doctors told Brooke on Sunday that if she wants to get better she has to reduce stress and get a lot of R&R in the coming weeks," a source close to Mueller tells PEOPLE. "Her mom is checking out spas around the country now."
Mueller has pneumonia in both lungs, which has adversely affected her breathing, and she is still in the intensive care unit of a Los Angles hospital where she has been treated with strong antibiotics for nearly a week.
Doctors treating Mueller, who previously battled addiction, are not happy with the slow rate of her recovery, blaming much of it on stress to her immune system. They are also concerned about her physical and psychological health.
"The doctors basically said Brooke is not going to get better without taking her health in her own hands and reducing the stress surrounding her life," the source tells PEOPLE. "She has to do it now."
Even though actor Charlie Sheen has been visiting his wife in the hospital daily since she was admitted last week, Mueller's mother, Moira Fiore, wants her daughter to spend some time without him.
"Moira wants Brooke to get away from Charlie, away from L.A., and away from all of the stresses that are hurting her immune system," the source tells PEOPLE. "She is checking out major spas on the East Coast to target both mental and physical therapies to help her daughter."
Sheen has been allowed to have contact with Mueller while she remains in the hospital despite a protective order against him resulting from his domestic violence arrest on Christmas Day.
There is no date set yet for Mueller to be released from intensive care. A hearing to modify the protective order has been set for Feb 8.