EL PASO, Texas -

Friday marks three months since a family was ripped apart.

January 18, Pablo Hernandez, 13, was killed when the family's SUV was rear-ended by an alleged drunk driver. His sister, Isabel Hernandez, 15, was rushed to the hospital with life-threatening injuries.

Earlier that day, Pablo and Isabel were busy with sports. Pablo had a doubleheader; Isabel was in a basketball tournament.

The family had convened for lunch afterward and their father, Jose Hernandez, left early to fill up his car. His wife, Patricia, was going to take the teens in her own vehicle and meet with him at the gas station a few blocks away.

But that didn't happen.

"I heard a loud bang and I looked down the street and saw a cloud of dust. Then I felt something," Jose said, putting his hand to his heart. "And ever since then it's been a nightmare I can't wake up from."

Jose admitted, Pablo and Isabel were not buckled up. Patricia agreed to their request to stretch out in the back of their Chevy Suburban because they were tired from their long morning.

It's a decision they'll all have to live with the rest of their lives. But instead of dwelling on the past, they're trying to move forward.

For Isabel, moving forward means learning how to move again.

"That first night at the ICU they didn't think she was going to make it through the night. She was connected to every machine you can think of. Maxed out," said Jose.

The crash left the teen with a broken vertebrae, fractured ribs and collapsed lungs. Doctors were forced to perform a tracheotomy to help her breathe.

Her spleen has been removed and one of her kidneys had temporarily failed -- putting her onto dialysis. The varsity basketball player at Horizon High School in Horizon City also lost 40 pounds off her once fit, athletic figure.

She's been transferred from Del Sol Medical Center to Highlands Rehabilitation Center. The Hernandez family allowed ABC-7 to sit in on one of Isabel's rehab sessions recently.

The athlete now struggles to extend or lift her legs, pushing her palms down on the wheelchair armrests as she quietly counts the repetitions.

Her brow is furrowed with concentration as she watches the therapist explain how a splint on her right hand will help her regain the ability to tuck her fingers into her palm so she can grasp objects.

To her parents, every struggle is an achievement.

"I feel like I'm watching a miracle," said Jose, as he watched Isabel from the far side of the rehab center's gym.

Jose described the mix of emotions that would often wash over him in the days after the crash.

"I felt like I was playing tug-of-war," he said. "I was making (funeral) arrangements for my boy while my daughter was hanging by a thread."

Isabel's medical state was so precarious, she was unable to attend her brother's funeral. Her parents only told her of Pablo's death in March, once she was transferred into rehab.

The girl's face immediately crumpled when the conversation turned to Pablo.

"I didn't believe it in the beginning. I guess I didn't want to believe it and it hasn't affected me too much being here," said Isabel. "But I know it's just going to get harder for me once I get out."

Jose said the brother and sister had been enjoying hanging out together as they grew older.

"They had similar likes in music," he said, adding they enjoyed sharing funny pictures they'd find on the Internet with each other. "They were getting closer and that made my wife happy."

Isabel's face lit up when she talked about the fun she and Pablo had in happier times.

"I remember one time we went to the store and he went dressed as a banana and I was dressed as a superhero," she said, smiling. "We just did silly things like that. Those were the best memories."

In her fourth week of rehab, Isabel's energy is now dedicated to recovering. The walls of her room at Highlands are decorated with a board covered with her goals written on Post-It notes, a poster of her idol, LA Clippers point guard Chris Paul, pictures of her high school basketball team -- and Pablo. 

During the interview, we witnessed another feat. Isabel walked without assistance for the first time.

The milestone was one mixed with happiness and sadness for Isabel's parents.

"I kind of think my son is helping her some way, somehow," Jose said, his eyes never straying from Isabel.

Not realizing her father voiced the same sentiment, Isabel later told ABC-7, "Every time I reach certain goals I thank (Pablo) and I pray to God. I just know that he's there with me."

Isabel was able to walk out of the gym and down the hall before needing to stop for rest. The therapists pulled out a measuring device and announced Isabel had walked 140 feet by herself.

She has come a long way. But still has a long way to go.

Julian Tapia, 32, was arrested and charged with intoxication manslaughter in connection to the death of Pablo Hernandez. Tapia's case is still being investigated by the El Paso Police Department and has not yet been turned over to the El Paso District Attorney's Office.