Uni-the-Unicorn!
Hero
There are lots of multi headed dragons that are not connected to the 7-headed dragon of revelations. There is, as far as I know, no explicit link with the 5-headed Tiamat of D&D. There is a more directly link to mythological Tiamat and the D&D Tiamat.I think he is referring to the multi-headed depiction of Tiamat in D&D.
I guess what I am saying is find the premise of the OP inaccurate or unconvincing.