Your son should file his own income tax return if he received a W-2 and Form 1099. Do not add those forms to your income tax return.
If you meant that you already filed a tax return for your son, then amend his return.
The W-2 and 1099 may change both federal and California so start the amendment process for both federal and state.
See How to Correct Federal Tax Returns and How do I amend my state tax return?
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