(فَرَاغَ إِلَىٰ آلِهَتِهِمْ)
He turned aside to their gods, meaning he went secretly to the idols that they worshipped. The root of *rawghan* (turning aside) is the inclination of a person toward a side in order to deceive those behind him; it is used here for the aforementioned action because it is what is appropriate in this context.
(فَقَالَ أَلَا تَأْكُلُونَ)
And he said to the idols—mockingly—"Do you not eat?"
(91)
From the food that is before you. The polytheists used to place food before the idols during their festival days to seek blessings from them. He used the pronoun for rational beings [i.e., 'Do you (plural)' instead of 'Do they'] because he was treating them as they treated them.
