Death as a gateway to 'another world' can be understood even if we think that there is no soul and 'everything is physical'! So the questions like whether consciousness is caused by the brain or something 'immaterial' has nothing to do with the question of whether or not there is life after death! The debate about the existance/nonexistance of 'the immaterial' as a way of underpinning or undermining life after death is pretty old fassioned, and is doomed to fade away.
To be specific, rather than positing someTHING 'unknown' such as 'soul' as a means of continuance of life, we can posit some 'unknown' BEHAVIOUR of the known things. Example of this 'behaviour' is what I may term it as 'death-life homeomorphism'.
A cup is homeomorphic to a torus in that you can mould a clay from a cup to a torus without 'cutting'. That is if how 'neighbouring' parts of the cup are connected is what matters, then changing a cup to a torus doesn't matter. But it looks like 'the cup is dead'!