The sibling who lives closest should not automatically inherit every family responsibility.

Proximity becomes policy without anyone deciding it. Whoever is nearest handles the hospital run, the repairs, the weekly visit, the emergency, because it is obviously easier for them, and each individual instance is true. The total is a very different life from the one their siblings are living, and it accumulates for years without ever being discussed.

If a brother or sister lives closest to your parents, ask what the load actually looks like rather than assuming it is manageable. Take something specific and recurring, and give money or time toward the parts you cannot do from a distance.