K.
This woman is divorced, has a kid, and is having an email and phone relationship with another kid (basically) who lives across the US.
I've been in your buddy's shoes, several times. The easiest way out is for him to point out that she's having an email and phone relationship with a kid who lives across the US, and there's no future in that. He should point out that she should hold tight until her residency is over, then hit the dating scene again. And not the computer dating scene, as it's filled with more kids like him that live across the country.
All those things can be done with respect and caring. Odds are she'll stay friends with him for a while, and eventually they'll stop frequenting the places that the other hangs out. Life goes on, and if anyone is going to realize that, it's probably this woman.
Edit: Well, whaddaya know? I didn't make a generalization like I thought I would. Hurrah!
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