As someone who is a crier, it is a self fulfilling prophecy for me sometimes. The more I don’t want to do it, the more it seems to happen. Crying can be even more shameful for boys.
Ask the therapist for tips on this. Also, talk about it openly with your son. Crying shouldn’t be shameful.
What helped me was a year of therapy and 10mg daily w Lexapro. I just had an incident where I typically would have cried but didn’t feel out of control and it finally didn’t happen after 45+ years. It was chemical for me. It just is for some people.