"Is your cousin sneezing?"

Translation: A te unokabátyád tüsszent?

[Arcaeca]

I always look at tüsszent and think of the French verb tousser "to cough" :P

[RyagonIV]

I always think about tissues.

[RaphaelSeitz]

Te can be omitted right?

[RyagonIV]

Sure, yes. In that case a becomes az, since the next word, unokabátyád, begins with a vowel.