Best Big Brother Invites His Terminally Ill Sister, 10, To First Formal Dance

Big brother with an even bigger heart.

Fifteen-year-old AJ Spader of Sioux Falls, South Dakota shared an important rite of passage with his sister Rebekah, 10, when he took her as his date to his first high school dance last month.

It's an experience she might otherwise have never had.

That's because Rebekah suffers from myelodysplastic syndrome, a type of bone marrow disorder that has, in her case, failed to respond to a marrow transplant.

According to Fox6News, the family has decided to forgo further treatment.

"I wanted to ask my sister because she's most likely not going to be able to experience high school — so I just thought 'why not ask her to formal?' " AJ told ABC News.

AJ went all out in asking. According to Inside Edition, he presented Rebekah with a poster that said, "I would be broken if you weren't my sister because you taught me how to be brave, and I would be blessed if you went to formal with me" in front his friends, whom he gathered at the family's home. 

ABC News reported that the poster recalled the Spader family motto of "Unbroken, brave and blessed."

The 10-year-old enjoyed the full experience of primping and dressing for the formal.

Rebekah got the full princess treatment, dressing up and taking pictures before settling down to dinner with her brother and his classmates. 

"It's fun to watch her live part of life where the disease doesn't creep in," her father, Tony Spader, told KSFY/ABC.

Watch KSFY/ABC's video report below.