@omnommai
I think he's just misunderstood. He has terrible parenting and communication skills, I'm not sure if he realise that.
I'm assuming he gave her the dagger to protect herself just in case and the "bear with it" is a clear indication that he didn't mean for her to commit suicide, he probably went to investigate without elaborating.
The reason why he send her to that room, again in assuming, is no one can go inside unless they're royalty, and no magic can be used, so I'm assuming he though it'd be the safest place for her while he investigates.
I might be wrong, but so far this is my conclusion. He clearly cares about her but doesn't know how to show/express it. Of course it doesn't make him innocent an without fault, but a father who originally cares and doesn't know how is worth forgiving and better in my standards than one who started to care after she changed her attitude.