Wow -- you two are really mentally in tune! You might find from the very start that you share a subtle, elevated kind of communicative bond. Your friend will wonder how you can know so much about them when they haven't even put most of it into words yet.
You'll be highly observant of this person from the start, able to tune right in to their subtle cues and draw an accurate picture of their individual nature from comparatively little information. The trouble here lies in the possibility that they'll take that rapport and understanding for granted. Your pal may come to expect you to understand them so well that they won't think it's important to verbalize their thoughts, needs and feelings anymore. In general, though, there's not much of a downside to this bond. Your buddy will feel heard and understood, which will translate naturally to support and acceptance.