Thank you, Happy. Plan to do just that...talk more to client. I asked myself everyone question except the one you posed!
To clarify - concern is most definitely not the cash itself or their client but the country in which they stated the cash came from (although I have zero way of knowing if this is fact and even if so, that does not make it illegal either). In hindsight, I may have "headed down the worry path" before I looked around at all the different options!
Thanks again!