Should kids spank their parents at that point?
...The elder of the species, through years of evolution, have developed an ingenious defense against attack in their weakened condition.
Their entire posterior/dorsal side is riddled with a series of seeping pustules commonly referred to as "bed sores". Those seeking to inflict damage upon the owner of these gooey barnacle-bearers in turn risk infection and disease themselves.
In such a way, Elderly Humans possess a passive, yet effective defense not unlike their aquatic companions, The Jellyfish.
In fact, you might say, that Humans approaching inevitable death are "Jellderly".