Usually the actual lead author is first, the assistant authors follow, and the advisor is listed last.

At least that’s how it is in (psychology and other?) PhD programs.

So Ray may only be supervising or contributing a small portion and is likely listed on all papers his team publishes.

One senior physicist I worked with advocated alphabetical order whenever he would come first in it!

Physics, too, which causes another interesting side effect: https://www.thetimes.co.uk/article/to-get-ahead-in-physics-y...