Complications from Lou Gehrigs disease.
Know ye that a prince and a great man has fallen. Rest in peace, Mr. Romney. You were my favorite principal. 
Did you keep in touch? Or was it just coincidence you found out?
Either way, it’s never easy to lose someone you respect, though I (fortunately) have no experience in that area.
Well, after his diagnoses Jim Romney became a public figure, strongly defending Oregon’s Death with Dignity Act. Here’s a tribute written about him: