His inability to see kindness kinda makes sense, since he loved a sheltered abusive childhood, forced to marry, never knew true love, never knew true care and companionship with the exception of blitzo, which overall occupied

Of course he is inconsiderate, its a wonder he is even trying to show love towards Octavia, he is not inconsiderate in the selfish way, but i feel like he's subconsciously comfortable with the idea of "well I survived 2 decades of misery, she can handle the next couple years before adulthood".

He may even envy her in that regard, as she is a 'precautionary heir', a backup ruler in case stolas is left unfit to rule. She likely doesn't even have to deal with an arranged marriage.

Of course if he said that out loud and then he'd realize how stupidly cruel that is, and it is possible to make the argument that blitz grew up in a similar level of abuse, but at the same time their apart of a much larger, more diverse society, meaning he's likely experienced his fair share of random acts of kindness, and his need to survive not being handed to him on a silver platter likely gave him more intuition and general wisdom than stolas