Before I get started, I just want to say, please please do not try this at home.
This is not normal. This guy was born special. It’s not a skill everybody needs to learn.
The guy taking the kick is a practitioner of Juko-Ryu Aiki Inyo Jujutsu. According to their website, they teach a number of different styles based on Japanese martial arts.
Simply being able to take blows to vital areas does not make you a good martial artist, and it doesn’t mean you’ll necessarily win a fight.
I’m not saying this guy doesn’t have skill, but if you look back into traditional Chinese martial arts and hard Qigong from China, you’ll find many who can do these sorts of martial arts tricks.
Martial arts is about much more than withstanding hard blows. True martial arts are a comprehensive tool for self-development.
I’m not saying this isn’t impressive, I’m just saying that you should approach martial arts with a broader concept of what there is to be gained.