This can be stated in active form. Alternate translation: "A friend should be faithful to the person who feels he is about to faint" (See: [[rc://en/ta/man/translate/figs-activepassive]])
This speaks of a person who feels hopeless and is overwhelmed by his troubles as if he were about to physically faint. Alternate translation: "who feels hopeless" (See: [[rc://en/ta/man/translate/figs-metaphor]])