Exodus 20:12 — "Honour thy father and thy mother" — is the only one of the Ten Commandments with a direct, material promise attached: "that thy days may be long upon the land." Paul in Ephesians 6:2 calls it "the first commandment with promise." The honor commanded is not merely emotional respect but active care — 1 Timothy 5:8 is explicit: "if any provide not for his own, and specially for those of his own house, he hath denied the faith." The theological weight of elder care is significant.
Psalm 71:9 is the prayer of an elderly person: "Cast me not off in the time of old age; forsake me not when my strength faileth." This prayer is in the Psalms, which means it is sanctioned — the fear of abandonment in old age is a legitimate prayer, and God receives it. For caregivers, this prayer from the person being cared for is a window into what the work is actually protecting against. The person in your care is praying this prayer, whether they say it aloud or not.
Commentary is from a charismatic Protestant perspective, drawing on KJV text and public-domain sources including Spurgeon, Andrew Murray, and Matthew Henry.