Photo of teen who took her 3-year-old brother to class makes mom's heart 'explode'

— -- As a much-older sister of four younger siblings, 17-year old Stiles Parish is used to helping out.

Which is why on a recent day she took her 3-year-old brother, James, to her high school.

Mom Candice Curry in San Antonio told ABC News a family emergency prevented both she and her husband Brandon from being able to pick up James. So they asked Stiles to step in.

"This was a one-time event; we have never had her get him from school other than this day. But it was an emergency," Curry said. "I figured she had gone to get him and taken him home. Later that day I saw the picture on her Instagram and realized that she had taken him back to school."

Little James promptly fell asleep in his big sister's arms at the high school.

"She told me that she didn't want to be counted absent and that she didn't want to miss any work," Curry said. Stiles is studying to be a nurse.

"She was in her clinical-rotations class, and the teacher gladly welcomed her little brother in. He was so tired from [his] school that he passed out on her and slept most of the class. She not only helped our family out but returned to her responsibility at school."

For its part, the school didn't mind James being in class with his big sister, according to Curry.

"Her teacher was very supportive and didn't mind him being in the class at all. He slept most of the time and if he had become a problem my daughter would have taken him out so that she didn't disrupt the other students. She attends an amazing school that clearly sees the value in family and education," Curry said.

The mom said she can now put to rest any worries she's had that the 14-year age gap between Stiles and James would keep them from being close.

"When I saw the Instagram post it made my heart want to explode. The tenderness in it is just the sweetest," she said. "The fact that he is sleeping so comfortably on her in the middle of a class full of teenagers tells me how much he trusts her. As a mom, it makes me so thankful that they have this kind of relationship, and I pray it will always stay this way."