This is basically a story about child abuse and pedophilia wrapped up in fluffiness à la yaoi. And I am not sure whether the fact that the pedophile and the abuser are two different people makes it better or worse. Oh, the poor kid.
I've read age-gap yaoi before, and some of them have been really enjoyable (Honki Ja Neekara, Sweep!, Not Equal and Yume Musubi, Koi Musubi to name a few); however, this one just felt so wrong. Maybe it's because Keisuke behaves like an elementary school student and looks like a middle schooler (though really the fact that he's actually 16 doesn't make the
situation any better). Or maybe it's that Hisashi (the predator) happens to be the one person in the entire world Keisuke trusts and can talk to. And with the other manga I could at the very least estimate how old the older guy in the relationship was. But in Suki no Mebae all I know is that Hisashi has already finished college, is living on his own and works in accounting. I mean, I guess I can estimate about a 10 year age gap between Keisuke and Hisashi, but it could be more and considering Keisuke is 16 years old, 10 is bad enough. Oh, also, apparently Hisashi has been in love with Keisuke (and I mean in a sexual way--I am not going to say romantic because it isn't) since the poor boy was 13 years old. THIRTEEN! What kid in his twenties is sexually attracted to a 13 year old? This is just beyond messed up.
Of course, the fact that Keisuke gets beaten up at home by his brother just makes the whole thing so much better (and it's not some brotherly squabbling, it's full on physical abuse).