Re: How did he achieve this sound??
It sounds like an LFO modulating RESONANCE, while the CUTOFF is opened in a sweep. That Resonant filter though has a very nice an distinct sound, almost like a Roland filter, but it could be Eurorack modular, or soft synth I suppose.
Not all filters sound the same, they vary from make to make, and can even vary in models of the same hardware that were made at different times due to different components etc.