>>54253853He only did this in Emerald Kaizo, only for Brawly and only raised the cap by 1 level.
EK is stupid hard, it was probably the hardest rom hack when it came out. But it was not designed with nuzlocke in mind. You had to overlevel and use the best pokemon available to beat it in a normal playthrough. Jan trying to nuzlocke it with not only the standard rules of 1 capture per route but also add the level cap on top of that was insane. Under these conditions, EK is nearly unbeatable unless you get certain encounters.
Brawly especially suffers from this, as with the normal level cap he's only doable with a very specific set of pokemon. If you didn't get all of them, you're screwed and you have to reset or play it out and lose 100% of the time. That's why Jan made the cap 1 level higher than Brawly to give more leeway to himself and all the other players that were doing a nuzlocke with his rules.