Wanting to be a compassionate ally

Wanting to be a compassionate ally My SO has shared that he had a severe stutter as a child and went to lots of speech therapy because of it. Despite having dated for several months, I never heard it until yesterday. He said it only returns when he has had or is about to have a seizure, and even then only sometimes. When I heard him, I was really taken aback but all I knew to do was be patient, let him finish his sentences and otherwise engage in normal conversation. He hasn't said anything about it and I don't feel it is my place to say anything either. Am I handling this the right way? Is there anything else I can do when/if it happens again?