Not just helicopters, but apparently one or more C-130 aircraft as well.
See BBC news clip
So 2 questions along with apology for some thread drift:
Firstly, would the Taliban be able to fly and service a Herc to any realistic extent, assuming the somewhat unlikely scenario that they would find an actual use for it?
Then secondly, why on earth would machinery of that strategic and monetary value have been left behind?
Machinery is left behind when the cost in human lives exceeds the value of the machinery - To get that machinery out,someone has to guard it while it it being prepped. If it's a helicopter that number will usually exceed the passenger capacity of the helicopter. If not, then as soon as the guards climb into the helicopter, the position is subject to being overrun and the helicopter is an easy target, now filled with people escaping.
No doubt the Taliban will force or otherwise encourage former Afghan forces into service. If any of them were trained to fly, the sure, the Taliban could, conceivably, fly them. However, they aren't much use to the Taliban unless as a transport for the leadership. I expect they were damaged in a way that they are irreparable except by building a new helicopter within the old fuselage sheet metal.