Can two people share the same vision, such that one of them dreams of a warning or good tidings for the other, and the other sees the same dream, even if they are in two different countries and interact in the dream? And is this possible due to medical reasons or a miracle from Allah? And is there any evidence for this?

The convergence of a dream among a group of people is possible and real, as happened to the Companions regarding the vision of Laylat al-Qadr (the Night of Power), which indicates its truthfulness and validity. Just as the convergence of news, narratives, or opinions indicates their strength and validity, the agreement of believers' dreams on a certain matter is considered true, because their consensus would not be upon error. Ibn Taymiyyah said that a dream can be from Allah, or a self-discourse, or from Satan, but the convergence of believers' dreams on a matter was true.