Only if imagination can move millions of tons of rock.
As an engineer and machinist, he makes a convincing case, especially when dealing with sound. He’s on to something but his conclusions seem just ‘stuck’ in there. Any sufficiently large explosion in a tightly confined space has the power to move any amount of rock - just depends what is used and how much of it. Dunn said one component was hydrogen gas - that would work.
I’m sure you don’t believe those pyramids were meant to be tombs ... so Dunn’s idea about their purpose is as good as the next, IMHO.