I seem to remember reading that NASO has a benefit for members that die during a game of cardiac related illness. I'll dig more for you and see if I can find anything but calling NASO up should yield the information you need.
Edit: Here it is. "Heart or Circulatory Malfunction Death Benefit — In the event of an officiating-related cardiac death, NASO provides $5,000 coverage."
http://www.naso.org/Portals/0/downlo...rance_2012.pdf
Assuming of course this official was a member of NASO.
And my condolences to you for losing a fellow official.