He is also the chief suspect in the murder of 21-year-old Stephany Flores of Lima, for which he is being held in Peru's infamous Castro Castro Prison.
"My son is sick in his head," the Dutch newspaper De Telegraaf quoted Anita van der Sloot as saying in an interview published on its website Sunday.
Police in Peru say the Dutchman has confessed to killing Flores. He is scheduled to be interviewed by a judge in Lima next week. Van der Sloot has told his jailers in Peru he is ready to clarify the Holloway case - but only with Aruban authorities.
The Van der Sloot family lives in Aruba, where the interview with Anita van der Sloot was conducted. She told the newspaper her son disappeared in mid-May, two days before he was scheduled to travel to the Netherlands for treatment in a mental institution. He left a note saying he was going to Peru, she said.
In the Telegraaf interview, Anita van der Sloot said she does not believe her son killed Holloway.
"But if he killed Stephany, he'll have to pay the price. I won't visit him in his cell, I cannot embrace him," she was quoted saying.
She continues on to say that her son's mental health had deteriorated since Holloway's disappearance. She also attributed his decline in part to media scrutiny.
In an e-mail to ABC News, Anita tries to paint a different picture of her son.
"He is not the monster the (media) would like the world to see," she writes. "He is traumatized, depressed and has an addiction. He is not a murderer."
She told the paper he had called her several days before Flores' death, sounding paranoid.
"He said he was being followed. He had been arrested together with a girl and robbed. He was not making sense," the paper quoted her as saying.
"I can't cry for Joran like I did for Paul. I hope that he gets psychological help."
The Associated Press contributed to this story.