Yes, he does go and visit AND he takes the girlfriend with him and they talk in front of Terri. Read some of the nurses affidavits about Terri's reactions after they leave. Of course, she has no idea what they are talking about so those reactions must have been like her smiling at her mother, trying to talk, etc. just muscle contractions, etc.
Even if it were told to Terri, she does not have the capability to comprehend the info.
Most likely only recognizes Michael by his voice.
Highly doubt Terri knows who the girlfriend is & that would "maybe" be puzzling to her.