The British-born 19-year-old, who travelled from east London to Syria to join Islamic State in 2015, wants to return because her newborn son is unwell and she does not want him to return to the United Kingdom alone.
Begum's family are from Bangladesh but the country said Wednesday she had no claim to citizenship there.
We are, as has previously been expressed through our solicitor, disappointed with your decision to begin the process of stripping Shamima of her British citizenship.
Her family said on Friday they were "shocked and appalled" at the "vile comments" she made in the media. "In all of this debacle, he is the one true innocent and should not lose the privilege of being raised in the safety of this country".
Begum, who is now in a Kurdish controlled camp in Syria alongside baby son Jarrah, and two other British-born women, also remarked on the lack of contact from the Home Office lead by Javid.
Asked about the situation on ITV's Peston, Mr Javid said: "I'm not going to talk about an individual, but I can be clear on the point that I would not take a decision and I believe none of my predecessors ever have taken a decision that at the point the decision is taken would leave that individual stateless". "I can't do much for him".
"I'm sorry to be so upset", she said.
We were pleased to learn from your comments in the Commons that you recognise my nephew, Shamima's son, as a British citizen.
Jordyn Woods breaks her silence at first public event since 'cheating' scandal
Jordyn's profile has been wiped from the #GoodSquad page, while a link to her original profile now provides an error message. This is the not the first time Tristan has been caught cheating on his girlfriend and mother of his daughter True.
The letter from Renu Begum shows that Shamima Begum's family - who have stayed out of the spotlight for most of the week - are now prepared to take on the home secretary in the courts, and in the media.
"I would like them to re-evaluate my case with a bit more mercy in their heart", Shamima Begum told Sky News from a refugee camp in eastern Syria.
Still upset, Rebecca said: "Of course, for the first hour when this story broke I felt furious and didn't like what she said". I don't think they are allowed to do that. She says she doesn't regret leaving Britain but now wants to return to give birth to her child.
Her family have written to Javid asking for his help to bring her newborn son to Britain.
They also say they plan to challenge Javid's decision to revoke Begum's British citizenship.
The home secretary revoked Begum's citizenship in a move only permissible under worldwide law if it does not leave the individual stateless.
George Freeman, who has served as Mid Norfolk MP since 2010, responded to news earlier this week that the 19-year-old would be stripped of her United Kingdom citizenship with a Twitter post outlining his opposition to the move. "But she does not accept her wrong", Ali said, opposing the stance taken by her other British relatives who had previously spoken out in support of her.
Her pleas to be allowed back into the United Kingdom sparked a storm of controversy, fueled by incendiary comments she made in interviews in which she expressed no remorse about joining up with the jihadis and suggested terror attacks on civilians were "justified".