His mother and little brother are dead, his sister is fighting for life in a Sydney hospital, and his father is now lost in floods - teenager Shanon Heidemann needs all the back-up he can get.
The 17-year-old Queenslander's mother, Jane Towers, and his brother, Jayjay Heidemann, 12, died when their car was involved in a collision with a truck on the Princes Highway at Berry, on the NSW South Coast, this week.
His sister Khloe is still fighting for her life in hospital after she was critically injured in the crash on April 4.
Family member, Belinda Hartigan, said the father of the three children, David Heidemann, 50, had not been seen since March 31 and was understood to have gone missing in a flooded area.
Shannon has searched flooded areas near Mondure, Queensland, for the father of the three children.
Family members were searching for him when the news of the Berry crash came.
"He has been missing for some time so we are not sure if he has been swept away in the floods," Mrs Hartigan said.
According to Queensland Police, he was last seen at Mondure, west of Murgon and grave concerns were held for his welfare.
"David Heidemann was last seen around 8pm leaving an address on Mondure Wheatlands Road, telling family he was meeting a friend on Campbells Road," police said.
"David was reported missing after failing to meet his friend and failing to return home.
"Police hold grave concerns for David as parts of Campbells Road are currently subjected to flooding.
"David is described as Caucasian, 170cm tall with a slim build, dark brown hair and hazel eyes.
"He was last seen wearing dark jeans and a black zip-up jacket with a green motif on the front."
Ms Towers, a Queensland resident, was formerly of Batemans Bay, and her mother Julie lives in Narooma.
She was travelling to the South Coast at the time of the accident.
Mrs Hartigan, of Wagga Wagga, said her daughters, Sarah and Phebe, had started an appeal for funeral expenses.
"The family is grief stricken and utterly heartbroken," Mrs Hartigan said.
"Their loss is unbearable."
Mrs Hartigan late on Friday said Khloe was "fighting as hard as she can".
