UP with thumbs?

Hey there and Aloha!

Quick question, in the video Aldrine is playing DDDDDU.
D = Down, U = Up
He is playing D with the thumbs obviously, but I can't see is he playing UP also with the thumbs or with the index?
Thanks in advance!
The song is 'Aloha Oe'
https://ukuleleunderground.com/2017/01/uke-lesson-109-aloha-oe-farewell-to-thee/

looks like he's just keeping the thumb in a neutral position and playing the ups and downs with it. When doing this sort of thing I tend to use the index on the ups or, more frequently, I use the knuckle on my thumb. However, that would throw the timing off...or at least require you to do some tweaking to achieve the same rhythm. I would suggest playing it like him if you want to sound like him.

Thanks for the help. Yeah think so, too.