I'm sure Thai has means to make both of these questions unambiguous with particles, adverbs, or some slight rearrangement. The ambiguity persisted not because Thai doesn't have the means to make it go away, but because the speaker didn't anticipate that it would be necessary, based on making unwarranted assumptions about the hearer's context frame.
Of course. Often the easiest way to make the ambiguity go away is with an extra question-answer. Some conversations end up requiring more TURNS than the English equivalent, but Thai's tersity leads to greater efficiency when the ambiguity is resolved by context and the Thai information exchange accomplished in fewer words or fewer seconds than English would use.
But "complexity" is not "efficiency" or "inefficiency." I thought the following relevant quote from my earlier post was interesting:
David Gil, "How Much Grammar Does It Take to Sail a Boat?" (pp. 19-33), argues that a minimal language (no morphology, no stem-class oppositions, semantic composition by "association") is generally adequate for human communication, and that some languages such as (semidiglossic colloquial) Riau Indonesian attain such minimality in conversational stretches and approximate it elsewhere. Other languages are much more complex (e.g., have cascading syntactic hierarchies), but such complexity is "hugely dysfunctional" insofar as such a language "forces us to say things that we don't want to say" (p. 32). The implication of the papers by Nichols, Dahl, and Gil is that languages can differ greatly in overall overt morphosyntactic complexity.
In many languages of the Middle East and to some extent Southeastern Europe, there are no neutral words for "aunt" or "uncle",
There are eight possible uncle/aunt relationships:
{older,younger} {male,female} sibling of {mother,father}.
Thai makes do with just four words.
When the uncle/aunt is an OLDER sibling, Thais tell us his/her sex. But when younger, Thais tell us the PARENT's sex.
(Strictly speaking there are 16 possible uncle/aunt relationships since the uncle/aunt's spouse is also denoted. But Thai and English both treat this without additional words.)
Instead of "brother or sister" Thai speaks of "older sibling or younger sibling". Many nicknames are used by both men and women, and more than once, my wife relayed a conversation; but when I asked "was Noi a man or woman", she didn't know!
However, I think all this has little or nothing to do with "language complexity."