Improve the bracketed part of the sentence.
Your son (will) have looked smart is a kurta.

The sentence expresses a past possibility, hypothetical condition, or a strong probability about a past look. The construction "would have + past participle" (would have looked) is used to express a conjecture or hypothesis about a past situation. Note: The word 'is' in "is a kurta" seems to be a typographical error for 'in', but looking at the bracketed modal verb, "would" is the grammatically correct choice to complete the logical conditional context.