I think at some height that becomes possible, but just going up would probably beyond the maximum altitude of most helicopters. However if the helicopters were to fly horizontally, the plane would develop its own lift and it could engage the engines and continue.
Vso on a transport category aircraft is way faster than a helicopter is going to carry it. You’d be better off just dropping it at a real airport, if you can lift it anyway.
Using multiple helicopters (OEW of the aircraft is 40 tons, so you'll need at least two helicopters) to lift the same weight makes you run into physical problems that haven't been overcome yet. It's really hard to reach some sort of stable equilibrium in such a configuration.
Russians are likely the people who have the most experience with that so far, and they opted for other solutions despite throwing spaceflight-money at the problem:
Maybe with modern technology and computer-controlled flight it could be made safe, but getting into that would completely defeat the point, which is to find a cheap way to move the plane.
the issue with dropping an airliner from height is by the time it gains enough airspeed, it no longer has control authority to pull out. Airliners are not really designed to go through a dive like that and come out in one piece.
Glide restarts of engines are possible (if not core locked) but it also isn't something done very often.
As long as it doesn't end up in a flatspin an airliner should be able to pull up from a dive. For an extreme example where this was tested in practice, in the https://en.m.wikipedia.org/wiki/China_Airlines_Flight_006 incident, a pilot lost control of a 747 & ended up diving 30k feet at speeds approaching/potentially exceeding mach 1, then pulled 5 Gs leveling off at 10k feet once he regained situational awareness, & they were still able to land safely, although there was some damage
IMO the bigger problem would be needing multiple helicopters pulling together - wind or the jet's engines might pull the helicopters enough that they'd crash into each other, & you'd definitely want to start the engines before freefall..
