Unhinge Target player discards a card in response no cards what happens magic faq

[more98]

If I play an unhinge and other player has only one card in his hand, an instant, which he casts in response,

is my unhinge countered since when it resolved he doesnt have any more cards in hand?
am i forced to target myself with the unhinge? what if i have no cards either?
Do i get to draw a card?

[Arix]

Unhinge resolves as normal. Unhinge's only target is "target player"". It's not a requirement that the player has a card in their hand. They won't discard anything, but you'll still get to draw.

[Sphinx]

although if the targeted player is no longer a legal target upon resolution, the whole spell is countered and you dont get to draw a card right?

[Arix]

Yup.