I have never heard that. Keep in mind that it doesn't necessarily require any kind of expertise or knowledge to write a book, so don't believe everything you read! Check the author's credentials before taking any advice therein.

I could find no mention of giving a dog beer doing a quick web search, I know some people give their dogs brewer's yeast to help keep fleas away, so maybe someone figured beer would do the trick, as it's a product of fermentation.