To claim the credit for dependent care, you need to claim the dependent. If your fiance claimed the child in question he is eligible for the credit. I am not sure why they wanted school records to show he lives with you.
It is okay for 2 parents who are not married to claim their children how ever they agree as long as you both do not claim the same child.
A qualifying person is:
- Your dependent who is under age 13 when the care is provided;
- If you live together only one of you can be Head of Household the other is single.
- If you live apart. The custodial parent has to sign a 8332 to release dependent.
- Bottom line only the person claiming the dependent can take the credit
