Now, his family and that of his fiancée Stephanie Anderson – a fellow ninth season contestant – are revealing to PEOPLE how he was hurt – and how he's finding the strength to recover.
The accident occurred on Sept. 3 in San Francisco when Poueu, after a night celebrating a friend's birthday at a dinner, went to the rooftop of another pal's apartment and the door locked behind him.
Poueu "attempted to climb down the fire escape ladder to drop down into the fourth floor balcony and slipped," the families say in an exclusive statement to PEOPLE. "The San Francisco Fire Department responded within minutes thanks to a neighbor's immediate call."
Poueu "suffered many serious internal injuries and a trauma to the right side of his head," the statement says. "Sam has made positive and encouraging strides since his accident. Since being admitted to the hospital, Sam has stayed strong through three surgeries. To date, many of his internal injuries are on the healing mend."
The families add, "He still has a long road ahead and is already a true testament to the power of prayer. Our faith remains that God will heal him completely according to His will. We are thankful for the miracles we have already witnessed in his recovery and are thankful for the dedicated medical personnel attending to him."
Plan to MarryPoueu, 25, a former security guard, started on the Biggest Loser at 372 lbs. and reached his goal weight of 238 lbs. well ahead of his season's finale. He has been working as a trainer at the Biggest Loser Fitness Ridge Resort in Malibu, Calif.
Anderson, 31, a senior account executive with CBS Radio, accepted Poueu's surprise proposal during the filming of a Biggest Loser special last October. The couple plan to wed in spring 2012.
Poueu's and Anderson's families say, "Please send well wishes, cards, etc. to: Poueu Family, PO Box 214, Cotati, CA 94931."
A trust fund has been set up to help in Poueu's recovery – click here.
"Thank you again for all your prayers," the families say. "Although he is in wonderful hands, we ask for your continued prayers and understanding as Sam and our families get through this difficult time. Praise God for our fighter Sam."
The families add: "We want to thank everyone for all of your prayers, thoughts, well wishes and support during this difficult time."