There are no embargoes in place. I guess the issue would be the possibility that the AH-1Zs were paid in part (or all) using FMF. However, the U.S. froze future payments, I don't know what it can do to retroactively suspend, that would just be punitive and a genuine sign of collapsing US-Pakistan defence ties (like the 1990s). However, the US DoD and DoS have been forthright about maintaining ties. The fact that the DoD is not worried about supply line closures is a clear sign that they're engaged with Pakistan. Finally, while political sides in Pakistan and the US are fuming, the bureaucrats and armed forces are trying to manage things.
The transfer of these birds, FMF and CSF is contingent on the DoD certifying Pakistan's work, so it's his word against Trump's fuming. It seems the DoD wants to sign-off, but he has to deal with Trump basically dismissing any real gains with a selfish tweet. If it's apparent that Trump is an unstable individual, then the DoD can bide its time and try to link Pakistan up via 3rd parties (e.g. Turkey/T129) to achieve strategic aims until Trump is out. Remember, in Carter's time the US had offered to link Pakistan up to financing sources in Europe for the purchase of Mirage 2000s instead of F-16s. If the AH-1Zs are canned then it's a matter of the US helping Turkey increase the loan to $2 bn so that Pakistan can get 45 T129 instead of 30. Remember, this is about aid money, not embargoes - so the LHTEC engines should, technically, be a go.