He loved tennis, bass fishing and playing worship piano at church, a talent he inherited from his grandmother, his father said.
He also enjoyed shooting, a skill he learned from his father, William Clayton Brumby. Target practice was one of those things Stephen was poised to surpass his father on at the gun range.
Because their parents keep guns in the home for self-defense, each of the seven Brumby children learned gun safety at an appropriate age, Clayton Brumby said.
"We wanted our kids to be aware of guns," he said. "I wanted them to be comfortable around them and understand them."
Nothing Stephen knew about guns, it seems, could have prevented his father from accidentally shooting him dead Sunday at a Sarasota, Florida, gun range.
'Every round in the gun is your responsibility'
Clayton Brumby, 64, pulled the trigger while trying to fish a hot shell casing out of the back of his shirt, according to the Sarasota County Sheriff's Office. The investigation continues, but there are no charges pending against the father, the department said in a statement Monday.
Clayton Brumby does not dispute the department's account and accepts responsibility for his son's death. He hopes the incident serves as a reminder to parents to be vigilant in anything they do with their children, bearing in mind that anything can happen despite the best intentions and preparation.
"The gun didn't kill my boy. I did," he told CNN.
"Every round in the gun is your responsibility. When it fires you need to stand to account for it. That's what I've spent the last two days doing, accounting for my operating error."
'I made a mistake'
Clayton Brumby brought Stephen and his 24-year-old son and 12-year-old daughter to High Noon Gun Range for target shooting, just as he did once or twice a month.
After Clayton Brumby fired a round at a target, the bullet casing was ejected from the handgun.
The casing bounced off a wall and fell into the back of his shirt, the sheriff's office said.
In an attempt to remove the casing, the elder Brumby reached behind his back with the hand that was holding the gun. While doing so, he inadvertently pulled the trigger, the department said.
The father said the round hit the ceiling and came down on his son.
"It was a very freak accident. I made a mistake," he said.
"It doesn't take but a split second for something to go wrong and that could be (the case) with a gun, it could be with the wrong medicine, it could be with any number of things."
'I can't fix this'
His middle son's death leaves a big hole in the family's heart, the father said.
Stephen was as sweet and gregarious as they come, always willing to help his mother clean the house, fix the television or log on to email.
To his youngest sister with spina bifida, he was her caregiver and best friend, his father said.
Stephen's family has set up an online fundraiser
for funeral and other expenses.
As he entered his teen years, Stephen was beginning to take an interest in family conversations around the dinner table about life's bigger questions, his father said.
His family had high hopes for him. After finishing homeschooling with his mother, his parents hoped he would follow his older siblings to college.
What would he have done? Clayton Brumby is not sure. Stephen was just beginning to focus his interests.
But his father is confident he would have been successful, no matter what he did.
"He had a heart that was bigger than he was," Clayton Brumby said. "He was always thinking outside the box."
The shooting has not changed his views of guns, he said. He still intends to keep them in the house and use them for self-defense of his home and family.
"I can't fix this. It's just a great loss, but thankfully we'll see him someday. I have a feeling he's on a great lake out there."