Has Anyone Bulk-Updated the Author on All Posts Before?

I have a client (expert in their field) that finally agreed to be listed as the author for content on their site. They review everything for accuracy prior to publishing and all of the content published is based on videos he's published. We've published nearly 100 articles over the last year+, all supporting content for his 'expert' videos. I wanted to change the author on these articles to his name but I don't want to get dinged by Google for doing so. The current author is just a placeholder; no name, no bio, nothing. Not even a brand author profile. Have any of your done something like this in the past? What was the outcome? Thank you!