The weight might not be an excuse. We'll have to see. It doesn't matter how much notice he's had etc. It's how his body naturally reacts. He didn't quit at all against GG.
That's an overreaction though, comparing tbto a lions den. Brook could have won that fight, it was physically possible. He was ahead on the cards at the time of the stoppage. I rank his chances of a win at around 5%. Not zero like you seem to think.
he was ahead on the cards because the fight was in the UK. the typical british decision was in the works if brook could have made the final bell. hell the ref probably would have carried him to his corner, like cleverly's did against kovalev.