What should be involved in church discipline for a church leader?
First, we need to keep in mind that the primary goal of church discipline is restoration to spiritual health. It should never be viewed as punishment. Nevertheless, to set an example and because church leaders are to be models for others, disqualification and removal from his former positions of leadership and ministry is certainly part of the discipline needed for church leaders.
This is evident from 1 Timothy 5:19-20, “Do not accept an accusation against an elder unless it can be confirmed by two or three witnesses. Those guilty of sin must be rebuked before all, as a warning to the rest.” (NET Bible). The text does not tell us who “all” is referring to. It could be all the elders or church leaders or a larger part of the flock, but not necessarily the whole congregation. Note the comment on this verse by Expositors Bible Commentary:
The context suggests that “those who sin” (v. 20)—literally, “are sinning” (present participle)—refers to presbyters. Such offenders Timothy is to rebuke “publicly”—literally, “before all” (enopion panton). Does this mean before the whole church or only before the other elders? The next clause seems to favor the latter: “so that the others”— hoi loipoi, “the rest”—”may take warning”—literally, “may have fear” (phobon echosi). “The rest” would normally be the other presbyters.
On the other hand, note the comment by The Bible Knowledge Commentary which shows that good Bible teachers and scholars see this differently.
When such accusations would then prove to be true, Timothy was to rebuke the offenders publicly, that is, before the entire congregation. In this way the remaining members could take warning (lit., “have fear”). Fear of the discipline of God, in this case administered through the congregation, is a healthy thing in a Christian, especially for those in places of leadership. Modern congregations that ignore church discipline do so at the peril of both the offender and themselves.
Regardless, something of this nature is in order as an example and a warning to all the leaders at least, if not a larger part of the body. However, discipline is to be both negative and positive. It should also include actions by the leadership in keeping with Galatians 6:1f to provide for the growth, change, and needed help to ensure (as much as possible) that this does not occur in the future. The person needs discipling or counsel and accountability by those who are spiritually mature on a regular basis and over an extended time until they are reasonably sure that there has been genuine progress and growth. Failure to submit to this, of course, would indicate a lack of genuine repentance and require further discipline and rebuke.
If after removal from office, he is repentant and continues to attend the church, he needs the love and care of the flock and demonstration of forgiveness and acceptance.