Judging this book strictly by its title, it's easy to be leery of BL Fans LOVE My Brother?!, especially if you've been burned by fudanshi “humor” manga before. That, however, is almost exactly the reaction Mimu Oyamada's first English-language release is looking for, because it's what heroine Kirika Amano does when she discovers that her shut-in older brother Teruo has become a creator of hardcore BL doujinshi based on his favorite in-world shounen series. Whatever Kirika thought Teruo was doing in his bedroom for the last four years, it certainly wasn't becoming a fan-favorite manga creator of explicit R-18 works, and she can't help but be shocked by the discovery. But to Kirika's credit, while she thinks what he does is weird, she doesn't reject him or judge him harshly for it, and by the end of the volume Teruo's work has become something for the siblings to bond over. Rather than a condemnation of fudanshi or fujoshi, BL Fans LOVE My Brother?! is a light look at enjoying what you love, no matter what your or anyone else's issues may be surrounding it.
One interesting aspect of the volume is that we never really find out what caused Teruo to become a shut-in in the first place. We know he's now twenty and that it's been four years since he left the house, so he didn't go to high school, but there are no hints (subtle or otherwise) about him having been bullied or anything like that. Based solely on the context, it seems most likely that he's suffering from untreated agoraphobia – it doesn't feel safe outside the house. While that can have roots in trauma, that doesn't seem to be the case here; it's more likely that his parents simply didn't know how to help him. Therefore when his doujinshi become popular enough that he wants to sell them at events, he enlists his younger sister to help him with that, something that their parents are plainly ecstatic about. Kirika also understands that this could be important for Teruo, so while she isn't thrilled about pretending to be doujin creator Amaterasu's public face, she agrees to do it. (It's worth noting that there's not much in the way of parental pressure here; they do really want her to do it, but they aren't forcing her.) It's all a sign of how well the Amano family functions, and if towards the end of the book we find out that Mr. Amano isn't great at social media etiquette, well, I'm sure many of us can relate.
The trajectory of the narrative is really two-fold: we have the story of Teruo easing into overcoming his reluctance to leave the house, and then we have the story of Kirika learning that what her brother's into definitely has its appeal. She's essentially thrown head-first into the shark-infested waters of hardcore fandom, and while she's a little weirded out by Teruo's work and its popularity, that's less because it's BL and more because her brother's drawing sexually explicit comics. Watching the two plotlines unfold side-by-side is part of what makes the book fun. As both Teruo and Kirika become more comfortable with the entire thing, they begin to rely on each other more easily and to work together. Kirika may not let Teruo out of the house in full geek mode as pertains to his wardrobe, but she also is genuinely touched that people love her brother's work so much. Meanwhile, Teruo may have taken the avalanche approach to explaining what he loves and why, but when Kirika begins to really get into it, he's helpful, encouraging, and enthusiastic with her. The humor may be a large part of this volume, but its heart really is the sibling relationship, and watching them bond is rewarding. (Please note there is no incest – the book goes a lot of places, but that's not one of them.)
It certainly does help that the humor doesn't feel mean-spirited, of course. While Teruo's unearthly beauty is meant to juxtapose with his otaku habits and hobbies, part of the point is not judging a book by its cover (so to speak), so that's almost expected. The fact that the series he's madly in love with is about big muscular high school boys does add to the humor, not because of the doujinshi Teruo creates, but because the series itself is so clearly over-the-top in its aggressive shounen-ness. In one chapter Teruo and Kirika go to a special theme café for the series, and the lines fans use to summon the servers and order are utterly ridiculous, to say nothing of the names of the dishes. Likewise Kirika's experience of fujoshi/danshi fandom is peppered with her both learning not to make assumptions and finding the entire thing utterly weird, while her trip with Teruo to an anime store's fujoshi corner (and it is explicitly labeled as “for women,” which doesn't stop her brother) is pretty funny. Some of the expected gags are certainly there, but almost none of them are at the expense of Teruo's dignity – unless it's something he does to himself, and that's an important distinction. This isn't about laughing at the silly man who draws gay porn, it's about his sister plunging into his fandom, and that really does make all the difference.
BL Fans LOVE My Brother?! may have a somewhat suspect title, but on the whole it's a fun book. Oyamada's art skews busy, but it isn't hugely difficult to read, and there are nice distinctions between their work, Teruo's, and anyone else's that pops up in the story. The translation reads well, and the story does feel nicely complete in its single volume. It's a just a surprisingly fun book overall, with a nice message about not judging someone for what they like.