The Bible commands Christians not to keep company or fellowship with a person who has been expelled from the congregation:
"Quit mixing in company with anyone called a brother that is a fornicator or a greedy person or an idolater or a reviler or a drunkard or an extortioner, not even eating with such a man...Remove the wicked man from among yourselves." (1Cor. 5:11,13)
Jesus also said concerning this:
"Let [the expelled one] be to you just as a man of the nations and as a tax collector." (Mt. 18:17) Because those listening to Jesus knew well that the Jew of that day had no fraternization with Gentiles and that they shunned tax collectors as outcasts, they realized that Jesus was instructing his followers not to associate with expelled ones.
This shows that loyal Christians do not have spiritual fellowship with anyone who has been expelled from the congregation. Not only that, but the Bible says that we should "not even eat with such a man." (1 Cor. 5:11) Clearly, even social fellowship with an expelled person should be avoided.
What about speaking with a disfellowshipped person? Consider: A simple 'hello' to someone can be the first step that develops into a conversation and maybe even a friendship. The Bible doesn't cover every possible situation, but 2 John 10 helps us to get Jehovah God's view of matters:
"If anyone comes to you and does not bring this teaching, never receive him into your homes or say a greeting to him."
For more, see
Expelling / Disfellowshipping
Let Us ABHOR What Is Wicked
Discipline That Can Yield Peaceable Fruit
Search For Bible Truths - ARCHIVE
Search For Bible Truths - Search Guide