It's a hoax. There's a website out there called Break the Chain that's devoted to providing accurate information to end nonsense like this. They reproduce the story your friend gave, and then continue as follows, with links provided:
"Before you put too much clout in NewsMax, consider they also brought us the Gary Condit Biker conspiracy. Newsmax is well-known for its "get it out first, get it right later" approach to the news. They revel in outrageous conspiracies and the believably bizarre.
The truth behind this one is that the Gold Star representatives dropped in on Senator Clinton unannounced, but she was out of the office. One thing led to another and the rumor that the mothers were rebuffed was created.
To make matters worse, NewsMax repeated the misinformation a couple of times in different articles and never printed a correction or retraction. (What can you expect from a "news" service that refers to an American senator as "The Hildebeast?")
The national president of American Gold Star Mothers told TruthOrFiction.com that her office regrets the misunderstanding and would like the rumors to stop as quicKly as possible. Help them out and Break this Chain!"
Here's the link to the website that has the correction:
http://www.breakthechain.org/exclusives/goldstar.html