In a sense, you are teaching at two levels. The first level is about the Bible subject under consideration. The second level is less obvious, but equally valid: You are teaching people how to read the Bible for themselves. You are giving them skills, tools and confidence for Bible study that will benefit them for many other Bible subjects, even when you are not present to guide them. This is important because many people have never thought for themselves in religious matters. They let human leaders do their thinking for them, which can lead to disaster.
[Jesus] told them a parable: “Can a blind man lead a blind man? Will they not both fall into a pit?” (Luke 6:39)
Lead your friend to depend on Jesus. His spiritual sight is perfect, which makes Him the ideal leader and guide. Show your friend how to learn from Jesus instead of following fallible men. Admit your own fallibility and keep pointing to the “one instructor” who is perfect.