After death the doctor.

Help that arrives after the harm is done cannot prevent it. The doctor’s arrival stands for a remedy offered only when its opportunity has passed.

The proverb criticizes delay rather than the value of help itself: an appropriate response becomes ineffective when it comes too late.

Use it when someone proposes a remedy or takes action only after the outcome it was meant to prevent has become irreversible. It can express frustration with a delayed response.