Relationships and breakups

My friend's relationship is affecting my life and it's not fair.

My female best friend started dating this guy a few months back. I had no problem with it but I wasn't happy about it either (don't judge so quickly guys).
My reason for not being happy about it is not jealousy, it's the fact that the guy she had fallen in love with was my friend (casual friend) and my neighbor. Yeah, now you understand why. I know this guy well enough to know he had the kind of issues she could not handle but she said she felt love so I couldn't spoil it. Deep down, I knew it was not love cause she was going through a bad breakup and she needed a shoulder to cry on and his was available. Well these are past stories, let's talk present.

My friend is currently having financial troubles and she's seeking help from family and friends, that includes me and her boyfriend.
We were all doing our best to help her until her boyfriend came to me with the news that his girlfriend (my best friend) had received money from someone we don't know and is hiding it from us so she could extort us.
I was as surprised as you are.
In case you're wondering why he came to tell me this, remember I said we were friends even before they met. And it's like a regular thing for both of them to bring their relationship issues to me. And it's interesting how they forget I exist when it's happy season.
Back to the story, he was mad that she didn't tell him, I wasn't mad just yet cause she always had reasons for all her actions and I was dying to hear this one.
When she was asked, she had her reasons like I said and I understood her but her boyfriend did not.

Long story short, they're no longer talking and I'm wondering what I had to do with it. I can't talk to one without the other getting angry and it's stressing me out.

Would it be weird if I advised them breakup?
Because that's what I feel I should do.