Khan isn't ever going to fight Brook. Brook has been begging him to fight him for years now. If Khan does fight him Brook will put another KO loss on his record. Canelo damn near killed him and surely made Khan's weak chin weaker. Khan has been a cherry picker at 147 on those rare times he fights at all. He did show some bravery by fighting Canelo for top dollar with a size disadvantage excuse if he lost. That doesn't turn him into a take on all comers type warrior. I'll be pleasantly surprised if a Khan vs Brook fight ever happens.
If Brook can make 147, he destroys Khan. But I doubt this fight ever happens. I think Khan would rather fight Kovalev than feel the embarrassment of losing to Brook in the UK.
Khan should have emulated Wlad a long time ago, both have fragile chins and one has dealt with his issue a long time ago whilst Khan keeps getting KO'd and dropped very early by bums in all weight classes, even amateurs.