Is your cat spayed/neutered?? Sometimes they'll try frantically to get out if they "smell" the opposite sex in season. I had one cat who hadn't been neutered yet, and he broke right through the screen to get at the females...
Do what you can to keep the cat from even getting to the window. Put something there so he cannot get in it. That may help. Divert his attention with some new toys or a nice scratching post. Good luck. I hope your dad does not harm the cat in any way.