«وَلَوِ اسْتَقَامَتْ كَانَتِ الْأَحْوَالُ فِيهَا مُسْتَقِيمَةً»
Had those days remained upright, circumstances within them would have been sound.
Law introduces a hypothetical contrary-to-fact condition. Istaqāmat / mustaqīmah share a root, giving the line a clear derivational echo.
The speaker cannot restore the earlier time; he can only imagine its continuity. This closes the arc of remembered security and allows the frame narrative to advance toward a new turn in the elder's fortune.
The overall arc runs from origins and remembered ease through youth to deprivation and complaint against time.