In sparring, I throw the lead jab and lead high kick a lot, and do that jab feint a lot. I think scaring people with the power hand so they walk to my left is a good cue for trying this combo. For whatever reason, people who spar me a lot, or who are just better, are hard to feint and hard to hit meaningfully with the lead high kick. So, for the question about what to do, idk, maybe he should work on his blood oxygenation so he feels mentally fresher and harder to trick with feints after half an hour of fighting or whatever.
I can't imagine he needs to change much. It wasn't like it was me that head kicked him. Leon Edwards has one of the best lead leg head kicks in the world for MMA so...shit happens.