Hello, thank you for playing, i'm sorry but only the latest version of Gzdoom is supported, even if your friend were to pass the OpenGL check, it still wouldn't run because that version of the engine is extremely outdated and would lack a lot of features used to make this project. Your best bet is to tell them to run it with LZDoom instead (you can find it in the same page of Gzdoom), but keep in mind that that's not supported as well so it will not look and play the same.