Using Visions to Prove Christianity True

A few weeks ago a friend of mine asked what I thought about a Christian using a vision that they had as a piece of evidence to persuade someone else of the truth of Christianity. My initial reaction was to reject them completely on the basis of being subjective. But I started thinking about it a bit more, and this is what I came up with to provide to her. 

Explanations of Visions
My first inclination is to say that no one should believe anything based on a vision alone (regardless of who experiences it). According to the Christian worldview, there are three different unique sources that could cause visions (two for sure).

Its All In Your Head
The first explanation that is compatible with all worldviews is completely naturalistic- a mental state of affairs that causes the person to experience something as vivid as real life. This can be affirmed  regardless of which worldview one adheres to. There is no guarantee that the content of such natural visions accurately reflects reality- especially from any non-theistic worldview- see Plantinga's evolutionary argument against naturalism. If the person who had the vision is a Christian and the person they are trying to convince is a naturalist, the naturalist is perfectly justified in rejecting the witness of the vision. The Christian would need to provide some supporting evidence.

In these states, the vision produced could support any claim about reality, or it could reject any claim about reality. Both possibilities make sense from this perspective. Since this explanation is compatible with all worldviews, anyone can explain a vision by appealing to the it- whether the content of the vision affirms or denies a specific worldview.