Not necessarily! It depends! It could be that the constant popups about updating the AV, about allowing access to trusted programs etc. constantly reminds him of the aspect of security and has this aspect in the back of his mind while browsing, so it may actually enhance security awareness. As in "I'm the sort of person who cares a lot about viruses, so much that I have an AV and adblocker etc., so I'm also the kind of person who doesn't just install any crap."
Installing an AV doesn't automatically reduce your defenses. Only if you over-trust it.
>> Installing an AV doesn't automatically reduce your defenses. Only if you over-trust it.
Recent news might point otherwise and there's a debate about it. Does an antivirus really protect you from a real threat? On the other hand, as you're running extra software you're increasing your attack surface, which makes you more vulnerable.
I've seen very clever people pointing to the latter and marketing efforts to make me believe the former. Still, haven't made up my own opinion. In any case, I stick to just Windows Defender and EMET (https://support.microsoft.com/en-us/kb/2458544) to mitigate.
Installing an AV doesn't automatically reduce your defenses. Only if you over-trust it.