Wow, telling a rape victim who was too scared to fight back that is was consensual sex, th...

I want to believe the granny is inocent...? ╥﹏╥

Don't. She's as guilty as the uncle, because she knew what was going to happen.

We don't know if the granny knew Bum would be raped or not.

Even so, she knew Bum was afraid of the uncle so she's guilty too.

to me she's sketchy, why ask Bum to change room, it's strange if they always slept together

Yes. She knows the Uncle has been beating Bum. It's doubtful she really slept through the nigh molestation too.

I don't know. Maybe she actually thought he'd be gone that night. Or to protect herself she sent Bum there, that still wouldn't mean she knew Bum would be raped. She was being abused by the uncle too.

I posted some other thoughts about the granny here http://www.mangago.me/home/mangatopic/1893075/ (sorry, I'm too lazy to retype the same thing atm)

Unlikely that she felt akin to Bum or cared for him very much. She was probably also probably more fearful of the uncle than of caring for Bum and vice versa.
Regardless, she says nice things when they are with the uncle, but shows her true feelings when alone with bum as she calls him useless and such and basically talks to him as if she is disgusted with his existence.
So no, I don't like either character, one is just deadly in a fluffy outer coat.

I didn't say anything about liking the granny. I just don't believe she knew that Bum would be raped (〜￣△￣)〜

There is no evidence so you cannot simply accuse the granny. You can hate the idea but you shouldn't hate granny because you assume her to know Bum was being raped. No, that's how it works. You assume on action but we are not a mind reader.

*That's not how it works.