Most “less lethal” methods work by inflicting enough pain that the perp stops resisting.
This doesn’t work when the perp is too high to feel pain.
A stun gun should have brought him down even if he was high as a kite. Unless the gun didn’t have enough charge. Should be 12,000 volts or more, to bring anyone down. Electrical charges causes a person to be physically, and somewhat mentally, incapacitated. even high as a Chinese balloon.