Yes. 

I'm sure it's possible.

Once I was sending healing energy to someone who was very sensitive psychically and she contacted me as asked why I was sending her golden sparkles.

If it was someone less sensitive, she might have sensed something from me subliminally that only manifested consciously as thinking about me.

Oddly enough, I checked the forum just now because had a feeling there might be an interesting question that someone was asking and I wanted to see what it was. If people who never met and know nothing about each other can interact at that level, then people who have an emotional connection certainly can.

The person you experience in your mind can feel the metta you send them in your mind.

I usually don't practice metta in that directed fashion, to one specific person, but I have sent healing energies to people who have responded to that.