Wow. I’ve never heard of total strangers recommending anyone for anything even after 30 minutes Skype interview. But if that’s common in your field, then I could see why you expected it from her.

I’d probably be hurt too and wondered if she has some kind of preconceived notion about him.

The whole thing just sounds like there is more to the story. Why hasn’t your cousin ever met your SO? It seems awfully long time to not meet family of your partner. 5 plus years? And why wouldn’t he ask people he actually knows for references. Why ask someone he doesn’t know. Is he having trouble finding jobs? Keeping jobs?