Step 1: Understanding the sentence.
The sentence refers to a person standing alongside someone, offering support during a crisis. The correct preposition should indicate companionship or standing together with someone in an event or crisis.
Step 2: Analyzing the options.
- With is used to indicate being alongside or together with someone, which fits the context perfectly.
- In refers to location or a state of being, which does not fit in this context.
- For indicates purpose or in favor of something, but does not fit the meaning of the sentence.
- By indicates proximity but doesn’t quite convey the idea of standing together in support.
Step 3: Conclusion.
"With" is the correct preposition to show solidarity or support in a crisis.
Thus, the correct answer is 1. with.
Final Answer:
\[
\boxed{\text{The correct answer is 1. with.}}
\]