There are exceptions, but in general a lawyer may not disclose any information that he/she has received in confidence from his client. The fact that he is your son does not alter this.
If the lawyer had a specific instruction from his client he would not be breaching confidentiality in telling you. But he might be wary of his client asking him to do it, rather than telling you himself so he might say to his client that he would not do it. I don't think the lawyer could be compelled to tell you.