Peaches Geldof, 25. was looking after 11-month-old Phaedra when she died suddenly and mysteriously at her home in Kent, it had been said.
A source close to the family revealed to The Sun that they hope the little boy will not have been "aware" of what had happened.
They said: "The hope is that Phaedra was so young he wasn't aware of what was going on. The most important thing is that he's OK.
"It is devastating for Tom that he wasn't there but it couldn't have been avoided."
Peaches was a dedicated mother whose children meant the world to her. In fact, in her final magazine column for Mother & Baby, she described her children as her "entire existence":
“Before having two fat little cherubs under two (who expect attention and military-esque devotion to their every need 24 hours a day), I lived a life of wanton wanderlust.
"With fun-loving friends from Los Angeles to London, I was lost in a haze of youth and no responsibilities. Other than work, there was nothing stopping me from having constant fun. But it was becoming boring.
"I wanted an anchor – I craved it. And, when I had two wailing, smiling, joyful little blobs of waddling pink flesh, they became my entire existence, and saved me from one of pure apathy."
She emotionally added: "Everything else was nothingness and it just… didn’t matter. I had the perfect life – two beautiful babies who loved me more than anything. It was, and is, bliss.
"I’ve achieved a sort of perfect balance. Right now life is good. And being a mum is the best part of it."
Peaches was found dead at her Kent country home on Monday in ‘unexplained’ circumstances and a post-mortem examination yesterday was 'inconclusive' about the cause.