Agree with you for querying this solution, with the boat being overpowered and a halyard run to the cockpit trying to get the genny down a probably stiff track is asking for trouble. There is a much simpler solution, wind the spinaker (or other spare halyard) round the forstay and sail to douse it. Dosn't make the neated stow but it will get the boat under control untill he gets in. I have done it for reel and it works with a bit of jigging but one of the reasons I dont like roller reefing is because it does this sort of stuff when it goes wrong!
Seeing that I do not run a square rigger, I think that I would have problems knowing how to go about "counterbracing the yards" on my boat.
Again, for the boat to "merely come to and fall off by the counteraction of the sails and helm" implies that the helm is not lashed and that there is someone hanging on to the tiller / wheel while somebody else is working forward.
Otherwise I would say that it would be quite impossible for a modern boat (as in, not long-keeled) to maintain a steady 'pinched' stance with an unattended helm, long enough to claw down a genoa. Certainly not on my boat, anyway. /forums/images/graemlins/wink.gif
Being a lapsed sailor maybe I have got a bit rusty but I think I would heave to and then, as Gandy Goose suggests, have a hack at the fouled warp on the furling drum before trying anything else.