Lately (few months) YouTube will not load whatsoever on my android phone nor tablet very often, activating a VPN fixes it instantly. Using basic YouTube app
It is possible. Maybe the peering from his ISP to YouTube is shit/ overloaded. That was an issue for Deutsche Telekom for a few years because Telekom didn't want to pay for better peering. With a VPN it is possible to get good peering to your ISP and YouTube and in return faster load speeds.