Almost everyone experiences some degree or guilt when a person close to them dies. Most guilt feelings are not based on fact, but grieving persons don't always think very clearly. Many guilt feelings relate to things people feel they should have done or said while the loved one was alive - a promised trip, a letter unsent, a word of love left unspoken. The feeling is that the deceased left the world unaware of those feelings or was disappointed with the grieving survivor.
This type of guilt feeling is practically useless. It will not bring back the deceased. There will not be another opportunity to correct the situation. Guilt is a wasteful expenditure of emotional energy. However, knowing that doesn't necessarily make guilt any easier to deal with. The lesson for us all is to do and say NOW those things that are important so that someday we won't have to be sorry for not having done and said them.