Jonathan, you said our misguided brother heading into ministry was using the language of "God calling me." I would encourage him that any internal sense of calling needs to be confirmed by the church externally. 1John 4:1 "Do not believe every spirit, but test the spirits to see whether they are from God...." This command is addressed to the whole church. This isn't to claim that the church has "more" authority than the Spirit. It's that God has saved us into a community in order to help us test the spirits together. Besides, many people make autonomous decisions without seeking counsel and then try to make their position impregnable with the subjective "God is calling me to do it" rationale.

As to situation #1, the family who has a member persisting in unrepented sin as a professing believer, I think a good place to start is Mark 3:33-35 "Jesus said, who are My mother and My brothers? ...whoever does the will of God, he is My brother and sister and mother." Or again in Matthew 10:34 "I did not come to bring peace, but a sword. I came to set a man against his father, and a daughter against her mother, and a daughter-in-law against her mother-in-law, and a man's enemies will be the members of his own household." Jesus redefines our family, and the truly believing family members need to agree with that in principle from the beginning of the conversation.

But I'd need to ask more questions. Is the immediate family member a spouse or an offspring? If he's a spouse with long-standing unrepentance, the situation is thornier, and I'd want to pray a ton and ask the advice of my elders. 1Peter 3:1 may apply if the sinning member is a husband. If the sinning member is a wife, then the husband still has a responsibility to provide food, of course (1Tim 5:8), even he doesn't eat it with her. If this is a 20 year old kid living at home because he refuses to work, kick him out (2Thess 3:10)! If the flagrance and repetitiveness of a gross sin poses a danger to the other members, is there also a social justice element that would need to come into play?

This is tough, but unless you other brothers can prove otherwise, and unless there's a missing fact that would change the situation, it's hard to see how we can ignore 1Cor 5:11 just because it hits us in the family room. But if the church is going to counsel a Christian family this way, then the church also needs to act like a family to them and walk with them through the process, probably through relationships built in a small group environment. This kind of ocounsel would have to come with a committment to fellowship and accountability. Let's not tell someone they can't eat with their spouse and then pat them on the back with a chipper "how's that working out for you?" Invite the spouse to dinner at someone's home occassionally (perhaps provoking the sinning spouse to a right kind of jealousy). Take them out for a meal. Pray with them through it. Love them through it.