Lily Allen's stalker "needs help, not jail", his family have said.
Alex Gray, 30, stalked the singer for seven years and is awaiting sentence after being convicted earlier this month of burglary and harassment.
Gray, from Perth in Scotland, started pursuing the singer by sending abusive rants in letters but progressed to banging on her door and spending nights in her back garden.
He was eventually charged by police after an incident last October when the singer awoke in the early hours to find someone wrenching at her bedroom door.
Allen has said she was made to feel like a "nuisance rather than a victim" by police, adding that the experience had left her "a changed person".
She said she was not angry with Gray and claimed "the system has failed him" and demanded answers from police.
Gray's mother Michelle has described how she had tried to get help for her son from the police and mental health services for years.
Speaking on the Good Morning Britain programme, she said: "I had no idea that he had been stalking Lily Allen and putting her through these years of torture.
"We knew he had a fixation with her but not that he had actually been anywhere near her. We just thought he had a fantasy in his head."
She added: "We knew he had a mental disorder and he had been diagnosed with paranoid delusional schizophrenia two years ago and he was meant to be on medication for this, but nobody was ensuring that that was happening.
"It escalated after his dad died. He got worse and we knew he was getting worse. We tried to get him help and nobody would help us at all."
His mother added: "He finds it hard to... separate what's real and what's not real, it's part of his illness, I think."
Kaylie Gray said the family has not had any contact with Allen.
She added: "We are really sorry that it got this far. It's horrendous what her and her family have had to go through and obviously we feel so horrible for her."
In an interview with The Observer, Allen said: "Until he gets the right treatment and the right help he needs, then I'm not safe. You can throw the book at him, put him in jail, but he'll still be coming out. And the victim is never safe."
A Metropolitan Police spokesman would not comment on Allen's case but said they take stalking and harassment "extremely seriously".