You can't really be angry with God because you don't know WHY it all happened. We are all put on this earth for a reason that we don't truly know and we're all going to leave under the same circumstances.
Perhaps your father accomplished what he was put on this earth to do, or maybe he WASN'T doing what he was supposed to be doing. Perhaps his body gave out due to lifestyle behaviors, or maybe a bargain was made before he came down here in the first place. We could have all chosen our own death dates for all we know! Death is certain and that is all we know to be truth. We won't find out any answers until we pass on ourselves, and it was meant to be this way for a reason.
Instead of being angry with God (who I'm sure had a good reason for taking your dad - meaning I doubt it was a random "hit"), take comfort in the fact that your father has gained the knowledge we have all been seeking since day one. His spirit is free now - only his "shell" has died.
I lost my father 11 years ago, my mother 3 years ago, and I'm only 38. I thank God in my prayers for letting me have them for as long as I did! My 10 year old son's father died suddenly 3 months ago - for HIM I feel badly.
Perhaps within this sad situation there is a lesson that YOU are supposed to learn in this lifetime. Try to focus your energies on that instead.
Anger is a natural part of the grieving process - it will pass in time. I wish you well.