all these unanswered questions, right? lols!! I reckons Niisan always liked his little bro and got married with the neighbor girl for the stability of his family. (obviously holding back his feelings towards his little bro as it is forbidden) then, he realises that his son is having sexual relationship with his little bro which made him a bit out of control and now he is expressing his hidden feelings to his little bro. This is pretty much love triangle of Niisan, his little bro and his son. Well, that's what I've gathered so far anyways. ლ(´ڡ`ლ)
No i think they are just brothers. Nii san was jealous because his lil brother felt in love with someone more than with him (it's kind of normal when Shinobu always got his brother number 1 in his heart). And he want to do something to stop Shinobu and HIS SON's relationship (he was a dad and a big brother, it's really difficutl for him). But as you can see, nii san cant do it with Shinobu because he always think of him as a cute lilttle brother, they never have sexual in their mind about each other.
yeah you're probably right too but... who is in right mind kisses his own brother like that thou...?!!! well, Niisan didn't show much attention towards his wife but to his little brother is like his gf more like attention given and that got me thinking that anyways. (Niisan doesn't kiss his own son like that either!) ╮(￣▽￣)╭
So like does Nii-san like Shinobu now? What about his wife? And why is Shinobu at one moment obsessed with Nii-san but then obsessed with Kazuomi the next? (￣ε(#￣)Σ