Josef Neumann, the father of seven children, was one of five people hurt in the violent onslaught Saturday night at his rabbi's house in the Rockland County town of Monsey and is the sole victim who remains hospitalized in critical condition.
"Doctors are not optimistic about his chances to regain consciousness, and if our father does miraculously recover partially, doctors expect that he will have permanent damage to the brain; leaving him partially paralyzed and speech-impaired for the rest of his life," Neumann's family said in a New Year's Day statement.
The family said one of the blows from suspect Grafton Thomas' machete penetrated Neumann's skull and damaged his brain. They said the victim also suffered other cuts to his head and neck and that his right arm was shattered.
"Our father's status is so dire that no surgery has yet been performed on his right arm," the family said.
As they keep vigil at Neumann's hospital bed, the family called on Jewish people across the nation and world to work together to stand up against anti-Semitism and asked victims of hate to share their own experiences on social media.
"We shall not let this terrible hate-driven attack be forgotten, and let us all work to eradicate all sorts of hate," the family's statement reads.
The family said Neumann, who is also a grandfather and a great-grandfather, has received prayers and support from across the country and asked people to continue to pray for his survival.
The attack occurred around 10 p.m. Saturday when the 38-year-old Thomas allegedly stormed into a Hanukkah celebration attended by about 100 people at Rabbi Chaim Rottenberg's home in the predominantly Orthodox Jewish community about 30 miles north of New York City, according to police and witnesses.
In the frenzied attack that lasted less than a minute, Thomas allegedly went after people at random, hacking them with a machete, authorities said.
People fought back by throwing furniture at Thomas until he fled the house, leaving a chaotic and bloody scene behind, witnesses said.
One witness, Josef Gluck, told reporters that he threw a table at Thomas and that the suspect chased him out of the house, yelling, "'Hey you, I'll get you.'"
Gluck said Thomas tried to get into the Congregation Netzach Yisroel synagogue next door to Rabbi Rottenberg's home, but the doors were locked from inside. He said he followed the suspect at a distance and watched him get into a car and driveway.
Gluck managed to get the license plate number and turned it over to the police.
Thomas was arrested at gunpoint about two hours later when a pair of New York City police officers spotted him driving in the Harlem neighborhood of upper Manhattan.
Federal prosecutors filed hate crime charges against Thomas. He pleaded not guilty and was being held on $5 million bond.
Police are also trying to determine if Thomas is somehow connected to the unsolved Nov. 20 stabbing of a Hasidic rabbi in the same town where the Hanukkah stabbing attack occurred, law enforcement sources told ABC News.
After he was captured, Thomas' family said he's long suffered from mental illness, but was raised to respect all religions. Meanwhile, a criminal complaint alleges his journal contains anti-Semitic sentiments, including references to Hitler and "Nazi Culture" on the same page as drawings of a Star of David and a swastika.
Thomas' family said he was not a member of a hate group.