In "The Quick One" by G. K. Chesterton, Father Brown was talking to his friend about a murder that happened in the hotel lounge after a very serious altercation between two men because of another man's speech about the teetotalism saying:
‘Well,’ said Father Brown, with broad-minded calm, ‘you started by talking about fanatics; and how a fanatic could do anything. Well, I suppose we had the honour of entertaining in this bar-parlour yesterday, about the biggest and loudest and most fat-headed fanatic in the modern world. If being a pig-headed idiot with one idea is the way to murder, I put in a claim for my reverend brother Pryce-Jones, the Prohibitionist, in preference to all the fakirs in Asia, and it’s perfectly true, as I told you, that his horrible glass of milk was standing side by side on the counter with the mysterious glass of whisky.’
Does "entertain about" mean "distract about" or "entertain because"?
And does "put in a claim for" mean "I'd choose .... instead of"?
And I'm a bit confused about the whole meaning that he wanted to convey, as this reverend brother wasn't the killer, and Father Brown knew that already!