A 12-year-old girl is the only survivor of a head-on collision in Texas that left seven people dead on Sunday.
The deadly crash occurred just before 6:30 p.m. on Farm-To-Market Road 2722 in Comal County, according to a press release from the Texas Department of of Public Safety, obtained by PEOPLE.
A black 2005 Ford F-150 traveling north veered into the southbound lane and struck a black 2007 Chrysler Aspen heading in the opposite direction, Texas DPS says.
The driver of the Aspen — Albertin Olvera Gonzalez, 39, of Converse — and four of the five passengers were pronounced dead at the scene, according to Texas DPS. Among the victims are Nancy Olvera Gonzalez, 44, also of Converse, and three children: two boys, ages 8 and 17, and a 6-year-old girl.
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Hector Daniel Jaimes, 25, identified Nancy as his mother and Albertin as his stepfather in the description of a GoFundMe campaign he started to support himself and his 12-year-old sister, the lone survivor of the crash.
The girl was transported to University Hospital in San Antonio in critical condition, according to Texas DPS.
"As for my sister Mia she's doing great," reads a post on Nancy's Facebook page, which was signed by Jaimes, who's been adding updates about the tragedy to the page. "Thank the doctors and nurses that are working around the clock to help with her recovery."
On GoFundMe, Jaimes also identified his three siblings who were killed in the crash near Buffalo Springs Crossing: brothers Christian Eduardo Jaimes and Diego Fernando Perez, and his sister Zia Giulietta Perez Olvera.
"Right now I'm still processing everything," Jaimes wrote on GoFundMe. "My whole family is gone and I'm not sure what I'm going to do."
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Jaimes saw his family "right before they left" for an outing on Sunday, according the fundraiser. He said he returned home from work around 2:30 p.m. to find them "getting ready to head out," adding that everyone was "dressed nicely."
A Life360 app alert Jaimes received Sunday evening indicated via text message on his phone that his family had been involved in an accident, he said on GoFundMe. Jaimes also wrote that he woke up around 8 p.m. when a state trooper was at his front gate door.
"That's when I heard of what happened to my family," he said.
Jaimes did not immediately reply to PEOPLE's request for comment.
The driver and passenger in the 2005 Ford F-150 also died at the scene of the crash, according to Texas DPS, which identified the pair as Jose Andres Ramos Vazquez, 26, and Camilo Martinez Tovar, both of Canyon Lake.
Jaimes said he has received support from friends, family and coworkers in wake of the crash. So far, the GoFundMe campaign he started garnered more than $21,000 in donations.
"Together I need the support of everyone to help me out," he wrote on the site, adding, "Please whoever is seeing this I need all the assistance that I can get."
In an post about funeral plans on Facebook, Jaimes wrote, "There is still a lot to do for my family, but I need to rest. There's going to be a lot of questions for everyone right now, but understand that I'm doing everything I can for my family."
An investigation into Sunday's crash is ongoing, Texas DPS says.