Tibalt Olyyant was the tuba teacher who collapsed and died in the montage at the beginning of the Season 5 episode Not Cancer. He was portrayed by actor Mark Beltzman.
While he plays the tuba, he starts coughing and coughs up blood, soon collapsing and quickly dying.
An investigation shows that although his lungs were diseased, he did not receive a transplant that should have affected his lungs.