My senior year of college I wrote to the provost expecting a close relative would die close to my exams. His sympathy was immediate, and separately from that, an obituary or other certificate would set the incomplete/rescheduling machinery in motion. He did not apologize or explain, so by presenting his personal sympathy and his professional administration of a system he was able to protect both the school's expectations and an emotional, stressed student. I think this is the best approach.