Vygotsky's sociocultural theory provides yet another interesting and productive way to consider the behavior of crying in the classroom, and how to appropriately respond to it.
In sociocultural theory, children are seen as learning from others and learning from their social environments. In Vygotsky's theory, these environments are thought of as having the greatest impact on the minds of young learners.
When a child is repeatedly crying, it may be really important to reach out to the caregivers/adults/parents in their life, to see if this is a behavior is presenting itself at home or in extracurricular activities outside of school. By asking this question, you are considering the other social environments that a student is involved in, and trying to determine if perhaps this behavior was learned in one of those environments.
Additionally, you might consider the culture that the child is brought up in, and ask if crying is considered an acceptable, normal response to everyday events. If this is the case, then the child might simply believe that their response is normal considering the events, and may not think much of their tears.
Lastly, one of the most useful ideas in this behavioral context is the value of pairing up the student with a "More Knowledgable Other" (MKO). By pairing up the student with an MKO, you recognize the MKO's strengths in regulating their behavior in other ways than crying, and you think that perhaps the student who has been crying quite a bit might learn from the behaviors of the MKO. This pairing of an MKO is common in schools with buddy programs, pairing younger Kindergarten students with students in the upper elementary.