I am so sorry that your child has had to become involved in the grieving process at such a young age.
 
Parents and volunteers will be appreciated for acknowledging what the children say to them and giving them some information, too. ("Yes, you will miss NAME very much, as will I because NAME was a very kind person and fun to be with here at school.)  Adults also should not shy away from demonstrating their own grief. ("This is a very awful day and I am feeling very sad.)  But, also to give a positive statement that reflects an outlet for grief, too (I am feeling very sad and maybe I will write in my journal about how I feel.  NAME liked to write, too)
 
Here are some things that are important to know about the differences between adult and child grief, as well.
 
First, adults tend to go through the various stages of grief as outlined by the infamous Kubler- Ross books.   Children do not.  They tend to skip around with stages and at times seem unaffected.  Teens tend to congregate together in support.  This can sometimes be positive, but also can be negative.  This age group needs to be monitored very closely when a friend dies, especially if it was due to special circumstances, such as suicide.
 
Second, children don't always know how to censor their expressions of sympathy.  I have unfortunately worked with many families who were experiencing grief.  Sometimes, they would become upset because a child was perceived as saying an unkind comment, such as "Where will you put _NAME__   toys now?"  However, in actuality children tend to think in more concrete terms and not as in depth, thus seeming as if they they are rude and have no ability to control/censor their comments.  Conversely, children can be a bright light among the darkness for many families.  Their ability to "tell it as it is" can be refreshing compared to adults who stumble through the grief.
 
Thirds, children will grieve, but in their own ways.  Several months will pass before a child may actually processes the loss.  Many times this will be triggered by another event, such as the death of a pet, end of the year ceremony and when a child sees the family of the deceased after a period of absence.
 
Fourth, children and adults need to know that there is help for all who need to move through their grief.  Some people find comfort with clergy, school counselors, mental health workers, or in the comfort of friends.  Others find journaling, taking an active role with an organization that was connected to the deceased or other forms of positive outlets to be constructive ways to help.  Try and be aware of people who are "stuck" and can't move on from their intense feelings of grief.  Seek help if this happens to someone around you.
 
I hope this answers your question.  Again, my sympathies to all.
 
The book I cited is On Death and Dying by Elisabeth Kubler-Ross
I also added a website from the National Association for School Psychologists that may have pertinent information for you.
 
Louise Masin Sattler, NCSP
Nationally Certified School Psychologist