In recent weeks, militant supporters have proclaimed in messages on Twitter and on militant websites that "the munshid Abu Osayed Al Madani" has come to Syria and joined the Islamic State of Iraq and the Levant, one of the most hardline groups fighting in that country's civil war.
Al Qaeda's central command broke off ties with the Islamic State in February, accusing it of causing strife with rival militants in Syria amid increasing infighting among them.
A Twitter account in the name of Abu Osayed Al Madani, apparently belonging to her ex-husband, is full of tweets from Syria about the conflict. Among them are appeals for reconciliation between Al Qaeda and the Islamic State.
During and after her marriage, al-Hassani watched helplessly as her three brothers, Bandar, Abdullah and Abdel-Meguid, were drawn one by one into Al Qaida.
Bandar, seven years older than al-Hassani, was detained by the Political Security Agency for two years.
When he emerged in 2006 he had become more religious — indoctrinated by militants he was jailed with, Al Hassani says.
For the next years, he associated with Al Qaeda members, while security agents harassed him, trying to turn him into an informant.
In 2009, Abdel Meguid, who was 16 at the time, was also arrested.
He was held for three years, often in a cell with hardened militant fighters.
At about the same time, Abdullah - who was two years younger than al-Hassani, disappeared from home to join Al Qaeda.
When the popular uprising against Saleh began in 2011, Bandar left home for the mountainous central province of Marib to join Al Qaeda fighters, she said.
The following year, Abdel Meguid was released from prison. The younger brother who loved dancing as a teen was now bitter.
"He only spoke about how much he wanted to blow himself up in the middle of Yemeni soldiers," Al Hassani said.
She pleaded with him to stay at home, but after three days, Abdel-Meguid left to Marib to join his brother.
From there, he went to the nearby province of Al Jawf for training in Al Qaeda camps, Al Hassani said.
Bandar was killed by a drone strike in Marib on Jan. 20, 2013.
The next day, a strike in Al Jawf killed Abdel Meguid.
Security officials confirmed the circumstances of their deaths to the AP.
Al-Hassani saw her brother Abdullah once before his death, in 2012.
She and her mother drove 19 hours to visit him in a village near Al Jaar, one of the southern cities that Al Qaeda took over.
Abdullah was there helping treat wounded fighters.
She was there for two days, and most of it she spent arguing with her brother.
Abdullah tried to recruit her, offering her fellow fighters to marry so she could become a "mujaheda," meaning she would cook and clean for the fighters.
She argued back that Al Qaeda defames Islam, that its fighters cut off the hands of thieves and execute people without really knowing if they are guilty.
Abdullah tried to convince her of the beauty of jihad.
He told her fighters smile when they die, knowing they are entering paradise — militant videos and photos often show the corpses of martyrs with blissful smiles on their face.
"I just get depressed when I see their videos," Abeer said.
It was their first meeting in three years — but it was a cold one.
Abdullah scolded her for not wearing gloves and for not covering her eyes with a mesh.
"Every time I tried to give him a big hug, he would move away," she said.
"It was like he disapproved of me and what I stood for."
Less than a week after they returned to Sanaa, Abdullah was killed in fighting with security forces.