This question asks about the wording for prayer(s) for the terminally ill.
This posting (Davening for the interminably ill) suggests that it is inappropriate to praying for the recovery of a person who is terminally ill. Thus, it is inappropriate to use the typical wording: healing of soul and body for such a person.
This posting says it is appropriate to pray for an easy death Is there a prayer "for an easy death"?
The current posting asks if there is traditional wording for asking for a kind, even quick, death.