I so well understand your reluctance. That said, please don't allow your son to struggle and suffer when there is good treatment for his disorder.
My own daughter had severe GAD (generalized anxiety disorder) when she was of school age. We put her in therapy, which helped some, still, she would be so terribly anxious about going to school every day that she threw up every single morning, despite continuing to do well academically.
When the time came when she was so anxiety-ridden that she was unable to attend social events (she was around age ten) due to her anxiety, her pediatrician suggested medication. The medication gave her a normal life. She continued with therapy and was better able to use the "tools" she learned in therapy when the medication helped to free her mind from the prison of anxiety.
My daughter is 37 now and teaches in university. It gives me chills to think of how her life might have turned out, had we not properly treated her illness.