I am so sorry for the situation.  Your children would probably have priority over his sister but that would entail their asking the court to intervene if the hospital will not oblige.  They should inquire about that to the hospital asap.  As for SS survivor benefits, they can only get them up to age 18 (19 if they are attending school) or if they are considered disabled under the law.  I am giving you a link.  Good luck.http://www.ssa.gov/survivorplan/onyourown4.htm