If the purpose of grades is to convey a student’s accomplishment, adequacy, excellence, compliance, effort and/or gain in learning, then they fail
I think grades are to convey PERFORMANCE in a specific course. I do also believe a single grade doesn't speak entirely on ones knowledge, but I do not agree with the comparison of a mediocre student to an exceptional student going through a tragedy. If you email professors about your situation, they will always extend assignments for you if it is a serious situation. At the worst, the student may need to consider dropping the class to save their GPA, or taking a semester break to cope. I think there are too many variables to completely make Grading the issue in academia.