Hi Mike
It's a little unfair when modern scholars criticise Curtius's work since the lad himself admits at the very outset that he is compiling the accumulated lore surrounding Alexander and says straight up that it cannot all be true. Arrian, though later, claimed to rely on Ptolemy and Aristobulus and though this cannot be the complete truth either at least his omission of recounted personal contact and conversations between the protagonists suggests he chose, unlike Curtius, not to include stuff he reckoned had to be simply hearsay and legend that had grown up about the guy. There's still a lot of guff there, I imagine. But at least he tried.
Since these surviving accounts started receiving intense review in more modern times there has been much speculation regarding what lies "between the lines", and I assume it is from one or more of these speculative works that the "refusal to meet Alexander" originated. A much more plausible scenario, especially since her intervention over the fate of the Uxii is generally regarded as reliable, suggests a person retaining quite a lot of autonomy and power in the as yet undefeated territories but who also was prepared to act as vassal (or even captive) after Darius's defeat and wield influence within Alexander's area of control too. This would not have been a unique arrangement and suggests a deal had been negotiated to both their satisfaction, though in fact one where any grandiose gestures of newly acquired "familial solidarity" could well have scuppered things for both sides - suggesting an imperial union rather than a conquest when in fact the latter was still very much a work in progress and the intent was to permanently end the regime that had prevailed in the area before. I would tend therefore to side with Arrian and simply skip over all the claims of "mother/son" statements from either party - the truth is probably that she neither refused to see him or became his bosom buddy, but that lines of communication were left open so she could use whatever authority and respect she commanded to help keep the lad's new "empire" from falling apart from within, and for this role she received concessions, I assume, from Alexander (though probably little more than that).
It would have been nice if we weren't forced these days to view the guy via such Roman prisms of empire and imperialism - the original Greek accounts, had they survived, might well have nipped most of these most romantic and dramatic interpretations of Alexander in the bud, leaving us with a rather sociopathic and inept ruler to consider and one easier therefore to understand as someone very likely distrusted and probably even despised in the main by his contemporary peers rather than the "golden boy" the Romans certainly chose to "large up" for their own reasons later.