Conceptually or scientifically, it's not possible to know for certain that dualistic interactionism is taking place. All one can do is believe or surmise/reason that dualistic interactionism is more probable than physicalism, but the veracity of soul/spirit-body interaction cannot be known apodictically through natural means (reason, observation or experimentation). While I believe that some kind of interaction is now taking place between God, angels and the material universe, I don't know exactly how it occurs--nor does anybody else on our planet. One way that such interaction occurs is probably through secondary causes: Jehovah uses natural mechanisms to interact with physical things (e.g., the water cycle, hydrogen fusion, and weather patterns); nonetheless, secondary causes likely do not exhaust divine causation. That is where things become murkier in my view. How does Jehovah's holy spirit guide the apostles and others "in all the way of truth"? Not even a dualist can definitively answer this question. And there's also the problem of overdetermination, which I have not yet pressed.
I also hate to repeat myself, but it's problematic to use something we don't know much about to explain another phenomenon that we do not fully understand. Immanuel Kant would caution us against invoking noumena (Dinge-an-sich) to explain phenomena. Now I'm not saying that I fully buy into Kant's famed distinction--he's only brought into the discussion because it seems that invoking divine causation to explain mental causation is possibly an ill-advised move. It is like invoking the largely unknown to shed light on something else that is not completely understood. However, none of what I've said up to this point is meant to deny that Jehovah created the world, guides his congregation by means of holy spirit, and has performed miracles in the past. We just don't understand how divine causation works although we believe it works. So then how can we use an unknown to explain another largely unknown? To illustrate, some Trinitarians appeal to the Godhead to elucidate human personhood. That move likewise seems ill-advised because we know less about how spirit persons relate to one another than we know about human relations. I intentionally refrain from mentioning how wrong the Trinity is.
It would take me some time to word matters carefully and spell them out as I would like, but the spirit world and the physical/material sphere are qualitatively different in my frame of reference (Isaiah 31:3). Does that mean I view heaven and the material world as two separate realities? It depends on what is meant by "separate." For now, I say that they're qualitatively different, which means that the spirit realm is non-spatial, non-material, non-atomic, and devoid of elementary particles, and does not have any physical bodies, is not bound to the laws of physics, contains minds that are differently constituted from ours, but interaction with the physical world is still possible. I would submit that a spirit/spiritual person became human and that some humans have become/will become spirits/spiritual. Hence, there is a slight difference in how I frame the issue (spirit "minds" versus spirit persons and human "minds" versus human persons). In other words, personhood is the basic template which determines how I distinguish the spirit from the material world.