Ferline, Ellen, and Isaac Milandu are slowly adjusting to life without their big brother.
"He was just so full of life - like he just had so many goals and aspirations for himself - that I feel so bad that he didn't get to achieve," Ferline Milandu told ABC11.
On August 19, 20-year-old Jospin Andre Milandu was trying out for the North Carolina A&T track team when he collapsed and died.
The medical examiner lists the cause of death as complications from sickle cell trait with physical exertion.
It was a revelation that shocked his family - who didn't know he carried sickle cell trait.
"When my mom told me about the autopsy - and I'm sitting here - I'm just thinking 'How can you die from it?'" said Isaac Milandu.
It's a question all three siblings want answered - since they too have all tested positive for sickle cell trait.
Common among African-Americans, sickle cell trait is a genetic blood disorder where the body makes sickle shaped red blood cells along with normal red blood cells.
"You had one copy of the gene that produces sickle cell disease and one copy of the gene that produces nothing. It's really a normal gene, explained Duke physician Christopher L. Edwards.
Sickle cell disease - on the other hand - often leads to a lack of oxygen to vital organs and episodes of pain when the sticky sickle-shaped cells get stuck in the blood vessels.
Sickle cell trait - which Andre had - usually doesn't cause any symptoms.
Edwards says tragic cases like this often motivates others to take action.
"There is more attention being placed on the idea of being sickle cell trait positive. People are beginning to think about it. People are remembering that they were told that they were trait positive 20, 30 sometimes 40 years ago and attending to that in conjunction with their primary care physician or hematologist," he explained.
Edwards says there's often a stigma attached to carrying the trait. People can feel guilty for having it and embarrassed to talk about it for many reasons - including fear of discrimination in the work place or when it comes to health insurance.
And because many who test positive feel fine, the diagnoses is often ignored. But it shouldn't be.
"That really is a challenge. How do you make it a functional piece of the medical history when it's in fact for many patients it's innocuous. It's not really going to manifest or bother them," said Edwards.
But Andre's story has a tragic ending. His siblings don't want to suffer the same fate.
"I want more information on what I can do. What are my limitations? How far can I push myself? What do I need to do to stay active?" asked Ferline Milandu.
They also want to educate others about sickle cell trait.
"Because us not knowing - we found out through an autopsy result - they should find out ahead of time," offered Ellen Milandu.
"I want everyone to be aware and just know what's going on with their body," said Ferline Milandu.
Andre had been running in 90-degree heat daily in preparation for the tryouts where the coroner says physical exertion led to his death.
All of his siblings plan to consult a doctor to find out how to best take care of themselves in the future.