Yes, it is wrong, but if one's family is going hungry, what does one do? I seem to recall that stealing less than $20.00 is only a venial sin. A loaf of bread is less than that.
Depends on whom you steal the $20 from. Is it a widow on a fixed income living in a hovel, or it is Bill Gates, Elon Musk, or Jeff Bezos? (I think I recall reading not long ago that Elon was actually in kind of dire financial straits. I'd hate to think of him living on frozen sandwiches from Dollar Tree.)
In drastic circuмstances, Aquinas teaches that all goods are owned in common. And if your family is hungry, and your community is so nasty and churlish that you cannot get help from anybody, then their right to their property has to take a back seat to the immediate needs of your family, especially your children (
a fortiori if your wife is with child). Pay it back later in secret, if you can.
I knew of one Caribbean island, struck by Hurricane Irma, where the owners of a grocery store which was in shambles, told people "just take what you need, we don't need it, and we know you do".