eius versus suus?

Cum pauper sit, tamen ille sibi videtur par regibus, cum filii parvi ILLIUS ad eum celeriter accurunt et cara oscula liberrime offerunt.

I was wondering why eius is used because the man in question is referring to his own sons but since the story in question talks about farmers in general leading the rustic life would that be the reason why? This story is #32 of Wheelocks 38 Latin stories. Thanks, Paul

Your question is somewhat obscure. First, it’s illius, not ejus. But never mind. It seems just normal. The subject of the clause is filii and you expect to have illius or ejus, not sui. You would use suus / se in reference to the subject of their own clause or in reference to the subject of a main clause.

The general rule, with exceptions occurring at some circumstances (namely in subordinate and relative clauses) is that suus,a,um, as well as se, are used when the person being referred is the subject of the sentence (so, “Pulsavit se.” — he punched himself), and ejus (ind) when the subject is some other one (“Pulsavit eum” — he punched him.)

Suam villam vidit.
He saw his own house.

Villam ejus vidit.
He saw his (=someone else’s) house.