Wow, he sounds like a great guy! Births, Deaths and Marriages weren't that bad, you only have to fill out a stat dec stating you don't know the father of your child. But my advice seriously is lying to Centrelink. Horrible people there, at least the ones I dealt with.
I wasn't as good as Chan and read through everyone's back posts, I'm just going to wing it so apologies if I do double up on anything.