I was going to say that this fellow doesn’t not understand sola scriptura, but it looks like you guys have it covered.
All appeals to Scripture are appeals to interpretations of Scripture. The only real question is: whose interpretation? People with differing interpretations of Scripture cannot set a Bible on a table and ask it to resolve their differences. In order for the Scripture to function as an authority, it must be read and interpreted by someone. According to “solo” Scriptura, that someone is each individual, so ultimately, there are as many final authorities as there are human interpreters.