Who dem be nigga

Why should it matter what her pastor says?

Pastor or no pastor, the guy isn't interested in her. You can't force love if it doesn't exist. There is nothing you can do about it but let her be. It will eventually dawn on her that the guy doesn't love her.

Allow her to make her own mistakes. She'll learn from the experience. That's life.

It hurts me to see her in love with a man who doesn't love her back.

I know.

But there isn't much else you can do apart from warn her. Sometimes, you've just got let things be and let nature take its course.

She'll learn. Harsh, but true.

@op, Efe have said it all. There is no much you can do, except to leave her to learn from her own mistake, its called.....primary experience.
If you tell her anything bad about the guy now, she might tell him what you told her about him, which may be a beginning of problem for you, so, let nature takes its course, she will learn from it.