Stick with this kind of plan. It's only been a few months, she'll either come around or she won't.
I can't say I blame her for being uncomfortable with a VENOMOUS snake (especially if you were handling it, which you might not have been). Perhaps ask her to try just letting him crawl across her hand while she's touching your hand? That way, she doesn't have to actively move toward him.
Your boyfriend is a jerk if he and/or you actually believed that line. I would have calmly explained where he could put his friend's snake and left.