“Just friends”???🤨

So my friend has been with her boyfriend for like a year now. She texted me today saying she’s having insecurities regarding a friend of his that’s a female.

She’s brought her feelings up to him and they’ve talked about it. He’s a pretty trustworthy honest guy, but she doesn’t trust the friend.

This friend of his recently broke up with her bf and has recently started texting/ calling my friends bf nonstop. Texting him things like ‘I’m lonely’ etc...

My friend also told me they used to like each other.

So, help me give her some advice here. What are your thoughts?