Unfortunately, her filing status would be single because the "Qualifying Widow with Dependent child", not just "qualifying widow", is the status you are referring to which she probably does not qualify to use.
The Qualifying widow with dependent child filing status requires her to have a qualifying dependent child and can only be used for two years following the death of her spouse.
Please see the following information from irs.gov:
Here’s a list of the five filing statuses:
- Single. Normally this status is for taxpayers who aren’t married, or who are divorced or legally separated under state law.
- Married Filing Jointly. If taxpayers are married, they can file a joint tax return. If a spouse died in 2016, the widowed spouse can often file a joint return for that year.
- Married Filing Separately. A married couple can choose to file two separate tax returns. This may benefit them if it results in less tax owed than if they file a joint tax return. Taxpayers may want to prepare their taxes both ways before they choose. They can also use this status if each wants to be responsible only for their own tax.
- Head of Household. In most cases, this status applies to a taxpayer who is not married, but there are some special rules. For example, the taxpayer must have paid more than half the cost of keeping up a home for themselves and a qualifying person. Don’t choose this status by mistake. Be sure to check all the rules.
- Qualifying Widow(er) with Dependent Child. This status may apply to a taxpayer if their spouse died during 2014 or 2015 and they have a dependent child. Other conditions also apply.
Please refer to the following link with any additional questions.
Filing Status' per IRS.gov
