It's not about commas, it's about "asides" (I just looked this up in a dictionary, I hope it's a correct term in English) - end it's true that he's using many of them, but I wouldn't necessarily recommend changing this. Rather, I'd think about assigning priorities to those asides and grouping them in relevant chunks, using parentheses, dashes and semicolons beside colons, because - as we all should know (and those who do not have a chance to learn) - this could substantially increase readability of his writing. Long sentences can be a pleasure to read as long as their construction follows some consistent plan.

Just trying to help a bit :)