And that's basically it. There's no other writing credit I could find. Here's his IMDb page
The news is from a blog post on Bioware's site introducing the new leads for the next mass effect game.
Bioware has always had among the best characters in video games. Say what you will about Dragon age 2 and Mass Effect 3 but there was incredible character work in there. Halo 4's story and characters, on the other hand, were a terrible jumbled mess of trash. That game made me hate/not care about every single one of its characters, even the ones I did like in past Halo games.