You are obviously not a Christian because if you were, you would believe what Jesus taught.
Lighten up pal. Only God knows who is a Christian and who is faking it. We are all at different stages. Some of us know the word better than others. Some are babes in Christ, others are fully mature in Christ. We all had to start somewhere. We all have to learn. It is a process. We all have to go through a growing process.
Maybe he wasn't familiar with the scripture that you posted and therefore did not understand the concept. I do believe that the greater works that Jesus was referring to are works that men do, but done by the power of God working through them as they are filled with the Holy Spirit working through them.