You will need to have admin access to the blog, for which you will need to know (at least) the email address he used for the blog, and the password (best case) he set up.
If you have access to his email, then you can go to the admin pages of the site (as in http://example.com/wp-admin ), and then do the ‘lost password’ thing. Enter his email address and check his email for a link that will allow you to set up a new password.
From there, it’s a question of making changes to the site to get the content displayed in the way you want.
If the ‘lost password’ thing doesn’t work, then you will need to get access to his hosting place and get into the database in the wp_users table to change the email address for his entry. Then do the ‘lost password’ thing.
You don’t mention your ‘geek’ abilities, so some of that (accessing/modifying the database) might be harder for you. If that is the case, you will need some geeky help to do that.
You can send me a private message if you want my geeky help. Good luck.
(Note: your problem emphasizes the need for bloggers/site owners/etc to have a ‘I got run over by a bus’ issue where the survivors need to take over things.)
Sorry for your loss.