Since her primary home is on Long Island she is a resident of New York State and her income is taxable by New York State.
Since she spent fewer than 184 days in NYC in 2024, for 2024, she is not a resident of New York City and she is not liable for the New York City income tax. NYC uses the same residency criteria as NYS.
**Answers are correct to the best of my ability but do not constitute tax or legal advice.