Amir Khan doesn't seem to care whether or not it's "unsafe" for him to fight Kell Brook, but he says he's not going to do it, simply because he doesn't like Brook, and doesn't think he's a big enough name to bother.
"He's on his route, I'm on my route, and we just don't agree with each other. Basically, I don't like him and I'm not going to give him the fight. Eddie Hearn can keep saying that he's massive, he's this, he's that, he's a big name: he's not."
Khan (31-4, 19 KO) added that he does respect Brook (36-0, 25 KO) as a fighter, but that he's looking only to fight big names from here on out. He mentioned a rematch with Danny Garcia, who holds the WBC welterweight title, for which Khan remains mandatory challenger.
He also mentioned possible matchups with MIguel Cotto, Timothy Bradley Jr, and Manny Pacquiao.
This could be a smokescreen from Khan, but it might also be totally legit. If Khan really just doesn't like Brook and/or Eddie Hearn to the point that he'd really rather not give Brook the fight, there are certainly other name fighters out there for him to face. Realistically, he might be able to get more money in the United Kingdom to face Brook than he would to face Garcia or Bradley in the States, but is it enough for him to care? It seems not, at least for now.
Still, bigger gaps than the Brook/Hearn-Khan divide have been bridged in boxing. Mayweather-Pacquiao eventually happened, and that was far more of a hassle to put together than this would be. But Khan just doesn't seem interested.