Yes, I spoke to him recently. He is indeed from the rare Scythian branch which probably split 10k years ago from mine. Who knows if more people test in Tajikistan and Afghanistan let say, probably more samples from his branch will appear.
In the meantime, E-PF4428 got its TMRCA updated, and now we fall fully inside the Neolithic time frame - 5500 years B.C. - this means that E-PF4428 were most likely part of the Cardium pottery culture that brought them to Western Europe; LBK is another possibility. I still can't exactly understand if my sub-branch returned from Western Europe or it was a core paleo-Balkanic remnant - it is still pretty obscure. Still the larger picture is now clear that they entered during the Neolithic period and that is good enough.