The children's aunt may protest the letter by submitting the proof that the children qualify for Earned Income Credit for her.
Qualifying tests that must be met are:\
1.) relationship (neice/nephew qualifies)
2.) age (under 19 or under 24 if a fulltime student)
3.) residency (must live with her more than 6 months during the tax year)
4.) support (child must not be paying more than 50% of their own total support)
The father may be entitled to claim the child as his dependent based on a divorce decree, but he is not entitled to EIC unless the child lived with him more than 6 months of the tax year.