There are a few reasons why you might not see posts on this friends page:

• whatever you want it to be might have no friends defined. If you are whatever you want it to be, you can edit your LiveJournal friends so they show up here.
• whatever you want it to be might have friends defined, but all of their friend's posts might be over two weeks old (according to the times on our servers), and thus wouldn't be displayed here.
• whatever you want it to be might have friends defined that post only protected entries that you can't view, because they haven't defined you as a friend in return.