Do not let him build castles in the air if there is no attraction for you. If he is a friend, he knows you, so he will be able to know what you mean. But be honest, and keep that friendship.
Talk with him and let him know what you thought, and get to find out what he thought. Discuss what needs to happen now, and this could be a learning experience or a cause of huge conflict. Talk with him to guide it not get out of hand.
Conflicts are common in relationship but maybe more in a blended family. Joan gives us the solutions.
Conflicts can be good for a growing relationship. Bernice explains how.