are they out on their feet

The phrase "out on their feet" is an idiomatic expression meaning someone is extremely tired or exhausted, to the point of barely being able to function effectively while still standing. It can also imply being near collapse or unconsciousness from exhaustion or injury but still remaining upright. The expression is often used to describe physical or mental exhaustion after intense effort, such as working long shifts, studying late, or enduring physical strain. In summary, if someone is "out on their feet," they are very fatigued but still standing or functioning just barely.