rey-jugnu are father-daughter and they do have a great bonding with each other more than pranati jugnu is close to her father no matter how much he shows that he cares damn but fatherly instincts does strike in open with intensity when kids are in danger the fact remains that they are father-daughter
we might not seen rey care for his daughter but he did bond with his daughter and they form a bond
Getting along is different and actually caring about someone is different. He got along well with her because she is fun and naughty and entertaining and both of them like troubling pranati and he needed them both for his own benefit so it's easier when you can atleast get along with one of them. He has never shown an emotion towards her per se. Even when jugnu was talking about how she used to get beaten up by people she worked under,he showed no emotion. Only pranati did. So far with respect to caring and showing emotion towards jugnu,he was on let's say a scale 2 and then suddenly he goes to a 10? I mean even till last episode it was shown that he cares for pranati so kept warning her about his family when it's equally or even more harmful for his daughter but he never spoke about her. They could have atleast shown him have some emotion when people called his child illegitimate.