Britney Spears' longtime manager Larry Rudolph has claimed the singer may never perform again amid her mental health battle.   The singer, 37, was scheduled to resume rehearsals for her Britney: Domination Las Vegas residency after rescheduling the concert earlier this year, but according to the former entertainment lawyer, Britney will not return to the stage. Britney's longtime manager, Larry Rudolph, tells TMZ, "As the person who guides her career -- based on the information I and a