Editing a minimalist theme from Auttomatic

My client is using a free theme from Wordpress, Dusk To Dawn. Unlike most themes, this one doesn't seen to have options to have a blog template with post summaries and links to the full posts, it's just a long page with entire posts from top to bottom. We've also enabled a child theme that customizes the home page to be an age-verify gateway and not, as far as I know, changing the page options above. Can you change the function of this theme to show only summaries on the Posts page, not the full posts?

The site: http://www.mydirtylittleblog.com

Thanks. Eric