The 16-year-old school boy and his trip to Iraq, which Hassan said was sparked by a school project, have caused a media frenzy in the US, with major news networks competing to interview his family.
His trip is all the more incredible as Hassan, whose parents are of Iraqi descent, speaks no Arabic and yet managed to reach Baghdad where he walked into the bureau of the Associated Press, a US news organisation.
The US military confirmed that Hassan had departed Baghdad on Friday, but his family is not sure when their globe-trotting son will arrive home in Fort Lauderdale, Florida.
Shatha Atiya, Hassan's mother said: "I'm astonished no one has contacted me directly with this information. But as long as he comes home safe, I'll be happy."
Her son was somehow able to secure a visa and leave the US on 11 December bound for Iraq without his parents' knowledge. He flew to Kuwait and then travelled to Lebanon before entering Iraq.
"It's unbelievable how this is happening. I'm just wondering, does he know the uproar he's caused?"
Farris Hassan's brother
Hassan had been studying the Iraq conflict in a school journalism class and wanted to experience the country first-hand.
Shanaz, Hassan's sister, told CNN her brother was in Kuwait en route to Florida.
Hayder Hassan, an older brother, said: "It's unbelievable how this is happening. I'm just wondering, does he know the uproar he's caused?"