I'm Lucy, and I'd be happy to answer your questions today. I'm sorry to hear that this happened.
Faking a pregnancy could be considered fraud. If she gets any money from him, or is trying to get money from him, that's theft. She could actually go to jail depending on the amount of money involved.
A lawyer could subpoena her medical records from her doctor, but that's pretty uncommon. If she is pregnant, there will eventually be either a baby or medical records that show that a pregnancy occurred. He doesn't have to pay her anything unless a baby is born, so it's not really worth paying a lawyer now (unless she's trying to extort money from him). He could just insist upon medical records before giving her anything. A subpoena requires a pending lawsuit or a good faith belief that there's going to be a pending lawsuit, so he'd have to have more than just her claiming to be pregnant to get the records. Most people instead would wait for the child to be born and then request a paternity test.
Unfortunately, there is no cause of action against someone for being less than truthful when dating. So-called "heart balm" law suits were outlawed decades ago. People typically don't want the government that involved in their personal lives, so the government is no longer in the habit of regulating consensual dating between adults.
I apologize that this was probably not the Answer you were hoping to receive. However, it would be unfair to you and unprofessional of me were I to provide you with anything less than truthful and honest information. I hope you understand.