I like those 3 simple rules....be an example first of all.

it's possible the guy might want to preach his religion to you. this is a great way of doing dawah insha'Allah and a lot of Muslims have come to Islam because of trying to convert Muslims to Christianity. in all the cases I've heard of, what caused them to revert to Islam (bearing in mind that it is Allah alone who guides) was the mildness and humility of the Muslim, and the irrefutable logic of Islam alhamdulillah.