I think doc Dan went to the US. The man from the other team told him that there was this experimental treatment over there, right? I think he sold everything and went with his grandma
grandma is way too old to travel.. the other team got what they wanted without his help (jaehyung fall etc.) so i dont think they care much about him .
He was never explained properly I think ? The most actual information we got is when he demontrated his power on his ' Legionaire interview'. Something like he can control both Fire & Water simultaneously.
"to be honest I think you are a piece of shit, best wishes, bye"