How to deal with an estranged family member

My mom has 3 siblings, and only 1 will not be invited. My parents are divorced, both helping with wedding, and while they generally don't agree they both have stated they do not want my uncle there. Only my aunt still talks to him. I haven't seen him in about 2-3 years. He has mental health issues. He is a patient where I work, and while it's no secret my uncle seeks treatment, he does not know I work there. I have communicated with him verbally in regard to patient care. He told my aunt there was a girl with my name and sounded like me and he asked my aunt if I worked there and she wouldn't confirm. The mental health facility I work at treats outpatient and inpatient. At some point I might come face to face with him. How should I respond if he finds out I am getting married, or even asks questions? It is unfortunate things have happened the way they did, and as much as he was a great uncle to me when I was younger, neither parent wants him there due to his several issues. Advice?