He's making fool out of my friend

HOW do | stop my oldest friend from making a fool of herself?

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DIFFICULT CONVERSATION: She doesn't know how to approach pal about her ex

Her long-term partner left her last summer. ‘The rat is all over social media with his new girlfriend. They've moved to Dubai and there are loads of pictures of them shopping and sunbathing. He looks deliriously happy, while she looks like a gold digger.

Meanwhile, my devastated mate is still pretending that they're together. I've just had a birthday card from her with his name on it. She continues to say “we” whenever she talks about what she’s been up to. his is tragic and very embarrassing.

T suspect his new woman is someone he met online. She's glamorous and looks supremely Confident - very different to my understated friend. How do I approach this?