As a former Methodist who converted to Orthodoxy, I can tell him to wait until the reasons for converting are more compelling than those for not converting. And, once converted, to accept what the church teaches, even if he doesn’t quite understand it. Don’t go in intending to reform or change the church. That is, don’t be what Frank Schaeffer is (or was) to Orthodoxy. For me, it all became very simple. I walked into an Orthodox church one Sunday morning and I knew I was home. He needs that conviction.
Just like a Lutheran lady who started on one end of town and went to all the churches. When she stepped into the Catholic Church, she knew she was HOME!