His illness is very serious -- especially at his age.
https://www.sfgate.com/news/article/Heart-attack-raises-questions-about-Sanders-14495377.php
https://medical-dictionary.thefreedictionary.com/myocardial+infarction
https://www.sfgate.com/news/article/Heart-attack-raises-questions-about-Sanders-14495377.php
https://medical-dictionary.thefreedictionary.com/myocardial+infarction