[Mobhack]

Get the best AAA gun you can get - ie best EW rating. Depending on period, shika or tungaska. Guns fire several times in a turn, so more opportunities once he is in range.

Same goes for any SAM you buy - get the one with the best EW rating to balance out the Apache's EW.

And of course, if you have attack helos of your own in your core, you can always chase him down with these, firing guns at close range. Especially if he is low in AAA assets, himself so your helos do not get chased with AA as they run after the Apaches.

If you have fixed wing air strikes, then plot these where his choppers are hanging out, one may well decide to take a pop at a helo.

If he likes to sit up in the sky motionless in the hover, your tanks can disabuse him of that notion with an APDS round into his face.