Blog software for Mac?

My elder son has an iBook that he uses for some school work. One of the key things he uses it for is a daily journal, where the teacher asks a question and he has to write a response. The teacher will then write a response back. Since he is autistic and still somewhat non-verbal, this helps with his communications skills and getting his thoughts out of his head. Over the last couple of years I’ve set up a couple of different schemes for him to do this, from HyperCard to an AppleWorks database. They work fine, but a blog would be much better.

For various reasons, I don’t want to have him to blog his journal on the internet. I would like to install blog software on the iBook (running OS X 10.3.5), but I’m not familiar enough with the back-end of blogs to know what would work.

Anyone out there have suggestions?