He freaks out any time people he loves is moving away or drifting away from him (emotionally or physically). He goes to extreme lengths to please those he loves to get them to stay with him. I’m no psychologist but those sound like indications of severe abandonment and/or attachment issues. He is extremely scared of his loved ones deserting him.
Aur Shayad yeh bhi ho saktha hai ki one he is anxious because he lost his father and brother suddenly and the result is his panic, anxiety attacks. And attachment issues because his mother refused to forgive, be with him and he was forced to grow beyong his years to cope up with the society. You must remember the scene where he says to Pallavi that no one gives him importance, how he is no one's priority?? That actually showcases his feelings. Which is why he was emotional when Pallavi said that she made him her priority. Or yeh bhi ho saktha hai, since he was the first born and his family was suffering to make ends meet, he was expected to be responsible and take their responsibilities on his shoulders when he himself was an adolescent. I think he must have been around 15-16 when the incident happened, hence his attachment issues..