Many years ago I had a student who was unable to perform on her own. She
literally could not do ANYTHING for herself. Sometimes other students would
help her when I couldn't. But I too witnessed tears of frustration. Finally I
went to guidance and asked them where the benefit was for this student. All I
could see was cruelty. Lo and behold she was supposed to be accompanied by an
aide. In her case it was the law. Once her "aide" no longer had a "free"
period, she had a grand time in art. Since then I check on the status of each
child whom I suspect of being "special" to see if they are supposed to be
accompanied by an aide.
Check and see what the story where you are. There may be an aide taking a
break while that child is suffering.