Oliver's mother, Elisa Pridmore, dropped her High Court application to have Audrey Donnelly jailed for contempt of court orders not to remove the boy from her care.
Mrs Donnelly, 45, apologised for what she had done, but said she did not know about the court orders.
Sir Stephen Brown, president of the Family Division, who jailed Malkin for
18 months a week ago, said he accepted that she felt obliged to help him because of their relationship.
'It is unfortunate you have been put in this position by the strong influence brought to bear on you by Oliver's father,' he said.
After Mrs Donnelly gave an undertaking not to seek to remove Oliver from his mother's care and control in future, the judge said he would impose no penalty for her contempt.
Malkin, 54, a businessman from Kent, who is serving his sentence in Pentonville prison, London, was in court prepared to give evidence.
The boy had been taken from near his home on 8 November. It was the third time Malkin had abducted him.
Mrs Donnelly said that they intended to give Oliver a 'nice holiday to cheer him up'. But the next day in Brussels, 'it was all over the front pages'.
'I couldn't believe it. I was so frightened, but it was the point of no return. We ended up in Egypt where there were reporters and photographers everywhere.'
They voluntarily returned to Britain with Oliver last week, and were arrested at Heathrow.
The judge, who was told that the Official Solicitor, as Oliver's guardian, had no wish to see Mrs Donnelly jailed, said he would record that she had committed a contempt of court. He made no costs order.
Malkin is to apply for care and control of Oliver, or at least reasonable access, at a private hearing next month.
Malkin's solicitor, Sandra Davis, said later that her client would 'be lodging an appeal against his sentence in the light of the fact that he has not only been imprisoned for 18 months but was also presented with a costs bill for pounds 180,000 from the Official Solicitor, Mrs Pridmore and the sequestrators of his assets'.