I was actually looking forward to the development of the latest "impossible turn" post. To me, there are two distinct considerations.
Firstly, is it possible? This depends on many variables. To quote a few: height, still air range from the runway, length of runway, wind, aircraft capability/performance.
Secondly, and probably equally/more relevant, the reaction of the pilot. I occasionally demonstrate the "impossible turn", showing that, under certain circumstances, it is quite possible. But then I point out that pilots are not perfect and when faced with a real engine failure their performance may well degrade beyond the point of successfully completing a relatively challenging manoeuvre.
Anecdotally, there are a number of fatal accident reports whereby pilots appear to have tried to turn back towards the airfield. I'm not aware of a similar, or indeed greater, number of incident reports indicating successful engine failure turnbacks.
One final point. I would have thought that a pilot with a significant number of hours on an aerobatic aircraft would have graduated beyond using airspeed as an indication of AoA (proximity to stall). Indeed, the reliance on the ASI during steep turns, especially when close to the ground, rather worries me.