Sam Lutfi testified in court Wednesday that only he was trying to help her stop abusing drugs, and that he had an oral agreement to be her personal manager.
After Spears' first breakdown, he said he urged her mother, Lynne, to fly back to California to see her, but that it took her 25 days to return.
Lutfi alleges in his lawsuit that Lynne Spears wrote a book that slandered him by portraying him as a predator, wrongly accusing him of hiding the singer's cellphones, disabling her cars and feeding her meds that would make her sleep for days.
In court Wednesday, Lutfi broke down on the stand. He testified that there was a backlash from fans after the book was published.
"People I knew were shunning me," he said. "There were websites created. People were threatening to kill me, wishing I was dead, people wishing harm to my family."
Lutfi alleges that Spears' owes him hundreds of thousands of dollars for services as a personal manager. He also claims that on the verge of the singer's second breakdown, her father punched him in the chest.
"He was spitting shouting and yelling," Lutfi testified. "He said I better leave or he would beat the hell out of me."
Lutfi's attorney showed a video of paparazzi hounding Spears, a scene that brought her mother to tears.
Later under cross examination, jurors heard about a different side of Lutfi: four separate restraining orders because of alleged threats he made to neighbors and others. He was ordered by the court to stay away from Spears.