"She has been ordered by the doctor to stay in bed for 72 hours," the source close to Mueller says.
Mueller's attorney had filed court papers asking that she be allowed to attend Wednesday's hearing in an Aspen, Colo., court by telephone, but the judge instead set the session for Friday because the law requires both Mueller and Sheen to appear in person.
Sheen, 44, was arrested Dec. 25 after Mueller called 911 saying the actor threatened her. A judge issued a temporary restraining order against Sheen keeping him away from Mueller but not their 10-month-old sons.
Mueller, 32, maintained that she wants to see her husband again. Her attorney Yale Galanter filed a motion to try to get the order's no-contact clause thrown out.
"Even though a court order has prohibited Charlie from being around Brooke, she wants her husband to see his kids as often as he likes," Galanter tells PEOPLE. "And the kids have seen their father several times."
"Brooke and Charlie will each be in court Friday morning," adds Galanter, "but they will not come to Aspen from Los Angeles together."