Basically, Slim’s fortune is made on a corrupt business deal with the corrupt president of the time (Salinas) who he was buddy-buddy with, followed by gouging the Mexican citizenry on phone bills for the last 2 decades. (Salinas’s PRI party made out well too, as Slim gave lots of money back to them over the subsequent years.)
I really don’t think he’s in any position to talk about charity.
So he paid $900 million for $110 annual profits? So a P/E of around 8? That's not an obscenely low price, especially if they already had complete market share and premium pricing. The only way to go from there is down, and it's a high capital business that'd most like need lots of capital improvements to stay competitive. For comparison, AT&T is trading a 12 times earnings, but that's in a much more healthy and stable market than Mexico.
I guess getting a 10% stake at 8 times earnings is an okay deal, but it doesn't jump out to me as a great deal. Would you be excited to buy a stake at that price in a high capital Mexican business with no growth potential because it's tapped out? I wouldn't.