IOS 8 update download to install later

I am not sure if I have posed this in the right place, but I have a problem. My dad wants to update his iPad 4th gen GSM to IOS 8, but he and the iPad are in Africa with very unreliable and slow internet. I was hoping there would be a way that I could download an update file where I am, and then somehow pass that along to him. Is there any way to accomplish that, or are we just out of luck.