It’s sad that these so called scholars are so uninformed and politically driven.
It would have been perfectly fine if they discuss how Old Chinese and Proto Indo-European might share somethings in common, which I’ve done. However, these friggin’ “scholars” don’t even seem to understand the changes in their own language, let alone other language families.
For example, in their proposed 葉落 and yellow cognate, in Old Chinese 葉落 would be /*l[a]p kə.rˤak/, which sounds nothing like yellow. Even if you take any Middle Chinese language, such as Taigi, hio̍h-lak and yellow don’t sound anything like each other.
Not to mention the etymology of yellow is Old German’s *gelwaz, which ultimately came from *ghel- in PIE, which means to shine, from which gold also derived from.
There’s no way that *l[a]p kə.rˤak became *gelwaz, and it’s even more stupid to suggest that the Mandarin pronunciation for 葉落 led the word yellow, as the word yellow existed before the Mandarin pronunciation, which wasn’t even the standard koiné as late as 1815. However, it does appear you can say whatever that floats the government’s boat and make a living in China these days.