وَاشْتَعَلَ الرَّأْسُ شَيْبًا
And the head has flared with greyness.
For this clause, al-raʾs being the grammatical subject is secure. The fire-source imagery in ishtaʿala is a strong rhetorical observation. Claiming one exclusive psychological effect for every listener is considerably more speculative.
Good analysis distinguishes certainty, strong interpretation and possibility. The Arabic text, its translation, grammatical analysis and a commentator’s reading should not be presented as having identical evidential status.