Grief and worlds colliding

Riley at 5th grade orchestra concert

Younger Brother had his first band concert last night. It was held in coordination with the orchestra concert. It took place in the auditorium that Central Middle School and the Arroyo School share. Riley went to Central. YB goes to Arroyo. And it's confusing. Even though Riley was a 6th grader when he died, he never got to play in an orchestra concert for 6th grade because he died in October and the first concert each school year is held in December. So the only two concerts he participated in were when he was in 5th grade. YB is in 5th grade. 

How can YB be playing in the band concert in 5th grade and Riley also be playing in the orchestra concert in 5th grade? The orchestra even played "Dragon Hunter," which was Riley's favorite piece of music. I looked for him among the cellos. He wasn't there. I also looked for him among the violas because he switched to viola in 6th grade. He wasn't there either. I scanned their faces, not recognizing any of his peers. That orchestra doesn't know Riley. There wasn't an empty chair for him; there weren't any green ribbons tied around anyone's arms in remembrance. I suspect if I had new memories of Riley playing in an orchestra concert in 6th, 7th, or 8th grade, it would make more sense. But I don't. So it's all mixed up, these two children performing at the same concert. 

Next year will be even more confusing because YB will be at Central as a 6th grader. And how can both of my boys be 6th graders at the same school?