Ok I am not sure I understand all of this, but just in case here goes:
You had an argument with your brother re: images of women in lads mags, and this was a brother accused of domestic violence towards his ex, when in fact in your estimation he was in fact a victim?
If I have that about right I think this response of his was telling:
"Read all of that from a mans point of view and think about how it sounds. I find it offensive in how weak and prone to brutish behaviour it seems to think men must be."
Now granted I have not read the article he is referring to, but that in my view triggered his abuse experience. Having been a victim himself, and to top it off being accused of it himself, it is entirely logical to me any article he reads that he detects paints men generally as women hating is going to trigger that sense of powerlessness (both in terms of the abuse, and more importantly the false accusation). In fact it likely will make him feel it reinforces circumstances that made him a victim in the first place.
Of course by the same token you've dealt with casual everyday sexism, so the debate itself is a topic that can push your buttons. In short, you were looking to your bro for solidarity against crap you've put up with your whole life simply for being a woman. Whereas he was looking for validation that no it's not fair to paint men as a gender in such a way that victimisation such as he experienced slip under the radar. Unfortunately sounds like you both missed each other's signals.
Now I am purposefully avoiding the rights and wrongs of the actual debate, as I think the subject itself was just the catalyst and not the underlying core of the problem. For the record, I do think the page 3/ lads mags release a steady stream of low level psychological pollution into our collective unconscious. I don't think banning them will solve the underlying, problems of some men's attitude to women. However A) I may well be wrong in that assumption and B) I don't think we'll lose much in the attempt, so perhaps we should give it try and see what happens.
Getting back to your bro, it clearly would help if he could see things from your (feminist) point of view, and if your husband is a feminist ally and your brother is friendly towards him, perhaps he could clue him in. Note I am not suggesting that because your hubby as a man can sort it out and you couldn't, simply that in the light of current hostility/circumstances he is a logical choice.
Anyway I hope it all works out for the best, and if I missed some fundamental element that render most of the above nonsense, please ignore me.