What should I have expected?

My 11-year-old son really let me down. I was very hurt by his nonactions. Does that make sense? Let me explain. Last night he had his music program at school. Most of the program was honoring the veterans (the program was held the day after Veteran's Day) and one song was truly touching. It was called American Tears and put a lot of people in tears. Not just the song, but the slide show that the students/teachers made to go with it. The pictures in the slide show were of family members (of the students and teachers) in the military past and present. Not one of those were submitted by my boy. I was hurt and saddened. He didn't bother to ask either one of us (my husband and I) if we had pictures of his new family's relatives that had been in the service. I know my dad was, my dad's father, my father-in-law. I had tears in my eyes not just because of the lyrics, but because my own child didn't come forth and ask about pictures. Maybe it's because he forgot. Maybe it's because he's adopted and didn't think about his new family's past. I really don't know.