Esaw Snipes-Garner, Erica's mother, said Sunday her daughter's condition was grave but the family hadn't given up hope.
Eric Garner's most established little girl, Erica, was a noteworthy power behind challenges for equity for her dad.
Erica, who is also a mother of an 8-year-old daughter, gave birth to a boy in August, said Snipes-Garner.
A message sent Christmas morning from Garner's Twitter account said her family asks "that you take this holiday to enjoy your loved ones and for self care".
"So my sister had another heart attack last night and she's in critical condition", Erica's sister Emerald Snipes wrote on Facebook.
He would later go into cardiac arrest and die. "Before, I was just kind of aimless, not sure what I was going to be doing".
Police interview of Melbourne rampage driver begins
The 24-year-old is expected to be charged with drugs and weapons possession, but the charges are not linked to the auto attack. The streets outside Flinders Street Station were busy with commuters and holiday shoppers when the SUV rammed into pedestrians.
Doctors said the pregnancy had put a strain on her heart, which doctors discovered was enlarged, her mother said. Despite Erica being in critical condition, her family is remaining hopeful for a Christmas miracle. "Please PRAY for her".
"I want our young people, especially our protesters that's putting [their] bodies on the line to bring racial issues to the forefront, to know that their vote matters", she said.
"Erica better get better soon". In the years since she has continued to advocate more broadly, against police brutality and in support of racial equality. He had been stopped for selling loose cigarettes.
A video of the 2014 confrontation showed a writhing Garner repeatedly telling arresting officers that he was unable to breathe.
Erica Garner calls for further justice and legal action against the police officers responsible in the death of her father, Eric Garner. The city of NY settled with Eric Garner's estate for $5.9 million in July 2015.
Garner, 27, became a nationally recognized activist after her father's death in 2014.