M$ have put backdoors/unexpected code into their software in the past
I remember, in the 90's that you could do something with excel and get it to make statements about Bill Gates.
So, are you saying he is mad? Therefore, mad not to run a/v? Even though, to my knowledge he doesn't get plastered with malware getting in? But then I know some who have been stopped dead with malware, despite having sophos, kaspersky and Mcafee.