Many of us mamas with brothers and sisters would probably do anything to help out our siblings when they ask. Whether it’s giving them a place to stay during times of transition, or taking time out of a busy day just to listen and commiserate. While such compassion is great, there’s one little boy from Philadelphia, Pennsylvania who is showing the world what brotherly love really means.

On March 8, 4-year-old Michael Pownall will undergo a bone marrow transplant in order to save his brothers, 4-month-old twins Santino and Giovanni, according to Fox 29. Shortly after birth, the newborns were diagnosed with chronic granulomatous disease, a rare genetic immune disorder that affects one in 500,000 people, mostly boys, every year. A bone marrow transplant is one way to treat the condition.

In searching for a donor, doctors at the Children’s Hospital of Philadelphia discovered that big brother Michael is a perfect match.

“He’s just like, ‘I’m a real-life superhero.’ He says, ‘I’m going to save my baby brothers’,” Michael’s mom, Robin, explains. “He could have said, ‘No mommy, I’m too scared and I don’t want to,’ but he’s ready to go, and he’s our real-life superhero.”

Robin adds, “He goes to the doctor when he gets the labs for the pre-testing and he says, ‘Look how strong I am,’ and he gives them willingly his arm to get blood work. The nurses are amazed. They’re like ‘I cannot believe how brave he is,’ and he really is. It gives me chills.”

According to the American Academy of Allergy Asthma & Immunology, chronic granulomatous disease makes the body highly susceptible to certain bacterial and fungal infections. The condition causes a person to become very sick from illnesses that would be mild in other people, and could be life-threatening if left untreated or not treated immediately.

Michael and the twins’ oldest brother, Dominick, was also diagnosed with CGD, but received a stem cell donation from an outside donor, Fox 29 reports.

Pownall’s sister, Casey, has launched a GoFundMe campaign to help the family with medical, transportation and housing costs. On it she states Pownall and her family only have one car, which fiancee Michael uses to travel to work, and are currently living with relatives.

Both parents have also quit their jobs in order to take care of their children, according to Fox 29; Michael stays home to take care of 4-year-old Michael and his big brother, Dominick, while Robin is with the twins at CHOP.

“It has been a very tough time for my sister and our family but I figured I would try to help in any way I can,” Casey writes.

This seems to be a case where adults are being inspired by a tiny superhero. Michael Pownall may not be Batman or Superman, but the 4-year-old is one amazing big brother.