At about 0:52 of the performance video you can see his strumming hand.

https://www.guitartricks.com/lesson/14107

Looks like he's playing the first 4 1/8th notes as quick downstrums, then the next series of 1/8th notes as up, down, then a quicker down & up on the final 2 1/16th notes.  Looks like the same pattern on the B7 & the A7.

I'd probably do alternate strumming throughout to make it more efficient.  But I think any way you can make those chord strums happen is fine. 

Hope that helps!