Lawyer calling about case from residency. Need guidance!

A lawyer just called me in regards to a lawsuit between a patient and one of the ED attendings at the hospital i worked at for residency. He left a voicemail saying i treated her and had questions for me and the case. How do I even go about proceeding? I barely remember any patient from residency and my ER rotation was 5 years ago when i was an intern. Is it a pretty benign thing to call back or do I get a lawyer involved? sorry if stupid/naive questions I feel like a fish out of water.