Your reaction to notify the author is exactly what I would have done.
But no more. I voted "keep" in your consideration for deletion. Deleting BUU's node alone would be ineffective as it leaves all the replies with solutions lingering, but these replies are valid contributions in their own right and deletion is not justified merely because they're in reply to a deceptive node. Further, any possible damage is already done at this point and cannot be averted by deleting the parent node, which would rob the replies of their context. An editorial amendment of the node might be called for, but deleting it would be counterproductive.
Makeshifts last the longest.