It may help if you can realize that he is most likely so wrapped up in his intelligence that he is not realizing he is talking down to you. If it is purposeful, shame on him! Sometimes after that amount of time in school an individual starts talking like they would write a research paper. Giving unwanted reasoning or details. Or perhaps explaining something you already knew that made you feel he was looking down on you as insufficient.
I would communicate with your daughter that you feel talks or time with him is awkward and you want to help make it right for everyone. Explain what aspects you are bothered by and why. Hopefully she can constructively talk to him as a mediator. Not as a gossip and manipulate situation though. If you can perhaps you can all sit down and discuss it.