My teenager thinks Christianity is fake

My 15 year old has been asking tough questions and basically told me he doesn't believe in God anymore. Says it doesn't make sense and a lot of Christians he knows are hypocrites. I freaked out a bit but my wife reminded me that his faith has to be his own, not just inherited from us. We're trying to answer his questions honestly instead of just shutting down the conversation. This is harder than I expected. Any dads been through this?