In French we would use the "pronom d'insistance" and say: "Toi, au moins, tu sais lire" = "At least, YOU can read." Interesting enough in the case of the third person singular you can even omit the main subject and just keep the pronoun as subject: "Lui au moins sait lire" where the "il disappears". Which makes the sentence above "Il sait au moins lire" meaning that at least he can read (even if he can write, for example), but definitely not comparing to anybody else who can't.
I think both of those sentences could mean the same thing in English, it all just depends on where you put the emphasis: "At least HE knows how to read" and "HE knows how to read at least" both mean the same thing with the emphasis provided. I'm not a native French speaker, but I imagine if you put the emphasis on the "Il" in the French sentence, it may may provide the distinction you're wondering about