The late 'Man in the Mirror' star had reportedly discussed his wishes for his kids - Prince Michael I, 12, Paris, 11, and Prince Michael II, seven, known as 'Blanket' - in the event of his death and was even planning to draft a new will to amend custody details.
A source said: "There was a lot of rifts in the family, but Janet was the one person he spoke to regularly and he made sure the children kept in touch with her too.
"Ultimately, he wanted Janet to look after the children, with help from his mother Katherine, and was planning to draft a new will to reflect those wishes. He trusted Janet implicitly.
"When he had health concerns, he had a talk with Janet about how much she meant to him and the children, and how if anything happened to him, he wanted her to make sure the children would be loved and cared for in the same way he was raising them. She told him of course she would."
Michael's most recent will, written in 2002, named Katherine as the children's guardian but Janet - who accompanied the children to their family home to retrieve their belongings after the singer's death last month - has the support of her siblings in taking over as primary carer.
The source added to Britain's Grazia magazine: "The family think this could be a great idea - they are supportive of Katherine, but although she is in good health, she is nearly 80 and they are worried she is not up to the task.
"Janet is blossoming into a woman with tremendous untapped maternal instincts. The children automatically turn to her for comfort and direction."
Tyler Perry re-works and Ntozake Shange's 1975 choreopoem/play For Colored Girls Who Have Considered Suicide...
Watch the trailer for Why Did I Get Married TooFor one week every year, 4...
I don't expect much from Eddie Murphy these days. For the past four years,...