The death of a spouse especially when involving long term hospitalization can result in an increase of the risk of death in the surving spouse for up to two years. There is an emotional burden and our emotions effect our immune system and other body systems also many times a person who is so focused on the well being of their spouse will set aside care for themselves. This is sad but hopefully it is not so in another place where Chris Reeve stands tall. I pray their son Will(13) has the strength to deal with this.
http://www.nih.gov/news/pr/feb2006/nia-15a.htm
I think stress can be a factor.