Hello again Riverside_Guy,
Assuming you mean their Wi-Fi download speed is 25 Mbps, this is technically considered "high-speed" internet. However, there are many factors to consider when it comes to internet speeds and whether they may be affecting their ability to use FaceTime. For example, their internet may slow down if they have multiple devices connected to the same network at the same time, or if they use a cable internet connection it may slow down during certain times of the day/week due to “internet peak hours” where many people are online at the same time. Also, upload speed has to be considered too since you're essentially uploading live video when you use apps like FaceTime.
In addition to you testing while you're connected to a different Wi-Fi network, you may want to have your friend test it out while connected to cellular data only. They can turn off Wi-Fi in Settings > Wi-Fi. If they get a good connection to their cellular data network, this could help narrow things down a bit more. You could also have them test on a different Wi-Fi network as well. If you've been able to use third-party video conferencing apps recently on your iPad using the same Wi-Fi network you used with FaceTime, it's likely your internet connection isn't the culprit. You’re definitely welcome to have your friend try a third-party app instead of using FaceTime, however, it's very possible you could run into similar issues if your friend's connection is what's causing the problem.
Cheers!
