Everyone within the US and/or otherwise subject to its laws is considered a constituent of Congressional representatives vis-à-vis the Constitution. All people

Everyone within the US and/or otherwise subject to its laws is considered a constituent of Congressional representatives vis-à-vis the Constitution. All people are counted under the census, citizen or not, regardless of immigration status. Much of the Constitution and its provisions including the Bill of Rights apply to all, independent of immigration status or citizenship. Natural disasters do not discriminate. Negative externalities due to emergencies do not discriminate. For these and many other reasons - including expediency, propriety, and basic human rights, dignity, decency, etc - FEMA doesn’t discriminate in this way when it comes to emergency response. It just doesn’t make sense for them to do so given their mandate, nor would it be legal for FEMA to do so.