If she signed part II for the 8332 form for future years then to revoke that she would need to submit a new 8332 with part III filled out that does not take effect until the year *after* part III is submitted.
If that was not done then he should just file a proper tax return claiming what he is entitled to claim and attach a copy of the 8332 form. Hopefully he only claims the dependent and child tax credit , the non-custodial parent can never claim the EIC and child care credit. He might also want to talk to his divorce attorney for possible court contempt action.
(This assumes that the child is minor child under the age of majority in your state. Once a child becomes an adult [18 in most states] the 8332 no longer applies.)
**Disclaimer: This post is for discussion purposes only and is NOT tax advice. The author takes no responsibility for the accuracy of any information in this post.**
