Hi Lichmanas,
Welcome to Apple Support Communities! We'd love to help in any way we can.
While the version of iOS on your father's iPad is no longer supported, we may be able to offer some helpful information here.
It's important to note that some websites may not be able to load properly or at all on older software, due to advances in website design and security. However, if he's experiencing this issue on every website, it may help to head into Settings > General > Date & Time, and verify that the iPad has accurate system time. This may be critically important when establishing a secure connection online.
If the issue persists, we can also recommend testing the iPad on another Wi-Fi network, to further isolate the root cause to the iPad itself, or the current network. If the issue is only occurring on your current network, you'll want to refer to the steps in this guide to ensure the Wi-Fi router has the recommended settings for optimal compatibility with Apple devices:
Recommended settings for Wi-Fi routers and access points - Apple Support
Have a great day!