I don't think it's a good idea.If the US sends 100 AH-64D and 100 Patriot PAC 3 to Ukraine it could potentially make an impact. Helicopters can land anywhere and fly low enough to avoid detection by ground based radars. Patriot PAC 3 can target high flying jets which can pose a threat to helicopters. But I guess Americans are just a bunch of penny pinchers. Won't even spend 100 billion dollars to people who fight and die for them.
Now, any weapons supplied to Ukraine may be acquired by Russia.
The Ukrainian pilot is loyal and admirable,they chose to take off even though there was no hope at all.In such hopeless circumstances, the ground forces often choose to surrender.
However, ordering them to continue their hopeless mission will inevitably spread the mood of surrender.
We have seen many videos of Ukrainian soldiers on the front line selling weapons to the Russians,who can guarantee that these pilots who have acquired new helicopters will not surrender to the enemy?
Even the wreckage of a helicopter is of great research value to Russia and China (but it is uncertain whether such technology sharing exists).Maybe they can find some complete missiles or radars on it.