For all our understanding and tendency to pity "more primitive" civilizations, we don't do particularly well at ritual. And the modern world has seemingly created the necessity for a new one.
Someone told me that that as life expectancies increase, we're going to encounter more cases of dementia. My aunt has just gone through the trauma of being verbally threatened by her husband of 50+ years, a man who has such severe Alzheimer's that he no longer recognizes her and, for her safety, he has just been institutionalized. She says that the man she loved is no longer there. I think she's right. We need a new way to acknowledge the "death" of a person that precedes the time when their heart stops.
I'm not sure what this ritual would look like, but it would probably be somewhat like a funeral. Perhaps a ceremony in which loved ones mourn the lost, shared memories and praise the "dead" personality they once so loved.
Whatever the actual ritual, I do feel strongly that we need a new designation for those who have "passed over" into a mental confusion and fog so thick that they've lost themselves and everyone they know. Their loved ones need a ritual to deal with the fact that they're "gone."
Without such a ritual, the poor family members have no real way to deal with their loss, or are left to process this without any closure. Perhaps a simple ritual could help.