He intended to give his son a certain name; is there any blame on him if he changes the name?

My Brother's family was blessed with baby boy and he made a niyat that he would name him AbdulMateen before he was born, but he was born he told the name to my father but he said he wanted to keep something else and he is very angry on him by keeping this name can you advise should he listen to my father or should he keep the name that he made niyat for is there anything wrong if he doesnot keep the name according to the niyat?. I heard that if you make a niyat and break it you should fast for 3 days or give food to the poor for some days.