Not sure why the hint says that, that's not true. उनके always means "their." उसके पास = he/she has, उनके पास = they have/formal he has. And there's no verb here other than है, the breakdown of the sentence is "near them is less food than you." and since "food" is singular, है is used and not हैं. The verb follows whatever comes after उसके पास / उनके पास. So पास = near, उनके = their, उनके पास = their near (near them is how we would say it in English) and that's how you use possession in Hindi, there isn't really a way to say "I own something" just that "Something exists near me" but holds the same meaning.