((Yoda))
Salvation Army has open food banks. Lots of churches also offer food assistance and income levels aren't taken into account.
If your son is getting food stamps, then he ought to automatically qualify for assistance from larger food banks. But, he probably will need to fill out a simple application. My experience with the local food bank here is that the past year or so has been pretty rough. Sometimes, you get lucky and there are lots of choices ~ but that's quickly becoming very rare here.

Hopefully, your area has more support. Best wishes to you!