The stressor of your best friend being in the hospital with a serious illness can be classified as a major life change.
The stressor of having your best friend in the hospital with a serious illness can be classified as a major life change. A major life change is a significant event or circumstance that brings about a significant amount of stress and requires a period of adaptation or adjustment. In this case, the serious illness of your best friend is a significant event that can have a strong impact on your emotional well-being and require you to make changes in your life to accommodate the situation.