I have to agree with Harold about him finding a Baptist church. Sounds like the debate is going no where and is becoming somewhat divisive. If he's been there for quite sometime and he's still not convinced by you or the elders or other members but still wants to learn, then maybe give him some of the literature people have cited for you to give him. If he's not really interested in reading something in-depth, then I would say he's not really interested in learning. He really can't expect the church to change its views on this. Also, I find it unfair of him to charge your church with the duty of convincing him of paedobaptism beyond a reasonable amount of time and effort which sounds like you and your church have done. If he's serious about staying and becoming a member, then he needs to do his research. If he's not serious about learning about paedobaptism, then I would gently nudge him on to a Baptist church.