people with experience,,when does death kick in?

current situation,,she is 85, given hospice,,outlived it,,renewed it, outlived it, renewed it again, outlived it, going for 4th renewel, most likely going to outlive it, has been bedridden this whole time, does nothing but scream all day and wants to eat all the time, oh and doesnt like to sleep much....for those that have been through this..when do they finally succomb to this terrible disease, you hear people die from it all the time but for others it certainly takes its time.