Hi GZ, sorry about the finger trouble.
I have never had any drama with T tails, but some aircraft can exhibit unfriendly characteristics. I once tried an incipient spin in a Mooney and it instantly flicked on its back and spun inverted. In this guy's case rudder authority would have been his main concern.
The footage, albeit not terribly sharp, showed a nose down attitude. He was probably trying to maintain a speed above or at Vmc to avoid a rapid wing drop & spin to the left. To keep straight requires a lot of rudder which in itself increases the drag as the fuselage restricts airflow to the wing. His drag problems either came from a windmilling prop or gear, or there was significant reduction in power on the good engine. Full power on the good engine should have been sufficient for a positive rate of climb provided the aircraft was configured for best single engine climb. If the prop didn't feather properly due to internal damage, that would do it, but hard to imagine as the prop is on a free turbine.
