I am trying sympathise with Shiva. It obviously hasn't been easy for him and he is getting confused by everything. There is clearly a lot of new information for him to process. He doesn't know about what happened seven years ago or even during that time. He genuinely believes the family has been living together happily till now.
But even then the way he treats Raavi is still unacceptable. He is extremely rude and says quite hurtful things to her. He could at least not behave like that in front of other people. For once consider her self-respect. If his 'mothers' deserve to be revered by other people, then isn't she also a mother now.
Sadly, this is not a result of his injury but something that has continued from earlier. It's really unfortunate it isn't ever called out and instead just treated as part of his personality and mannerisms. This is not some harmless quirk which should just be accepted, rather something that needs changing as soon as possible.