Today my 12-year-old son asked me how much daddy makes. How do I have this convo with him? How much do I disclose?

I think you can first find out why is he asking the question to determine how to answer the question. For example, was it related to something he learnt in school? Is he contemplating asking for something? Sometimes, how we interprete a child's question may not be what he/she is asking. Will be good to clarify first before deciding on which answer to give. :)