He cant understand why his daughter must sacrifice her life for Dev after all, she is the apple of his eye and the reason for his life. Their entire life revolves around Kaajal and to accept that she is an adult and wants to take her life in her own hands is very difficult for any father to accept, much less a close knit and possessive family like Kaajals.
But the minute he realises that Dev himself is not wanting to marry kaajal for the same reason, he mellows down against Dev, which shows that he has no malice or anger towards Dev but his frustrations are only towards his daughter who intends to take a step which is a sure step towards her own death, which a father cannot tolerate or bear.
If only some pundit or someone comes and puts them out of this dilemma.
Maybe Dhruv kidnapping Kaajal will break the deadlock, maybe seeing dhruv torture Kaajal or hold her against her will, will make both the men realise how important she and her happiness is to them and maybe Satya might believe that it is better for Kaajal to be happy with Dev than unhappy all alone or unhappy with Dhruv or any other man