A 4-year-old from South Philadelphia is proving that heroism and courage know no age.
Michael Demasi Jr. volunteered to save the lives of his twin baby brothers, Santino "Sonny" and Giovani "Gio," who suffer from a rare immune disease called chronic granulomatous disease (CGD).
The condition weakens patients' immune systems and make them more susceptible to deadly germs and infections.
How, exactly, can a 4-year-old save the lives of his 4-month-old brothers?
The answer is in the bone marrow.
"The doctors said 'We have some good news finally. Your 4-year-old son is the perfect match for both the twins,'" Robin Pownall, the boys' mother, said.
On March 8, Michael will undergo a procedure in which doctors at Children's Hospital of Philadelphia will extract bone marrow and then transplant it the very same day.
"I'm really scared, exhausted, overwhelmed, in shock still," Pownall said. "It's a lot of emotions all at once."
But Michael has an important goal in mind.
"I want to save their lives," Michael said.
This wasn't the family's first brush with CGD. Their oldest son, Dominick, was cured of the disease when he was young. Pownall wasn't surprised when the twins tested positive because it primarily affects boys.
"That's not good because we have all boys," Dominick said.
Pownall and the boys' father, Michael Demasi Sr., have been taking turns staying with the twins.
Once it was discovered that Michael was a perfect match for the babies, the parents had to weigh the potential risks that the 4-year-old could face while saving his brothers.
The family remains optimistic about the outcome, and hopes to reunite sometime in April to celebrate the twins and the hero who saved them.
"I'm never gonna forget what he did," Dominick said about Michael. "Even though sometimes he's a pain, I still love him and I love my little brothers too."
The family has a GoFundMe page.