My 2 year old was kicked in the head.... ?!?

long story short i am going through a custody battle and i am just getting around to listen to these tapes and have heard that my son was kicked in his head!!! I am unsure what to do! This occured a week ago. I had NO IDEA and would it be crazy for me to carry him to the doctor even though it was that long ago? He is screaming hysterically on this audio and the father didnt even take him to the doctor nor did really pay it any attention. he just told the 4/5 year old dont do it again! not even pick up my son to see if he was ok! any advice?