You should not call directly. If the relationship was broken off by mutual consent than you have a better chance with her. If you broke her friends heart, unless your “ex’s” mental health issues are blatant and obvious to everyone, her friend may regard you as the bad guy (prior contact not withstanding).
She may or may not feel comfortable dating you, but it’s certainly worth asking (have someone she respects do it for you).
Years ago, someone sought me for a shidduch, who was previously married to a roommate from seminary. He was religiously what I was looking for, but it so creeped me out and I felt so much like I was betraying her that I declined the shidduch. Go in with an open mind, hopeful, and know that any possible snags may or may not be about you.
Hatzlacha!