If you are so untrustful, as I have said in a previous discussion when the unity news had just come out, simply restrict the internet access. Many softwares use Telemetry.Like I said, it's a personal choice whether you trust them enough to use their program. I use VSCodium over Visual Studio when making Ren'py games to strip all the telemetry out.
An engine's size doesn't matter, a blank project size does, which I assume is much smaller than Unity anyways, which makes it a good point I agree with.My point stands: Godot (50MB) is still smaller and lighter than Unity (1GB) yet it's still very capable for 2D games despite it's small size.
In fact, it is kind of what held me back from making something with Unreal so far (aside from learning a whole new engine), an unreal blank project is much bigger than Unity's.
However, Ren'Py and RPGM are light as well... If he wants to make a 2D RPG, he may as well go for the easiest option, as for Ren'Py, if he needs to learn his first language, Python is a good option.
While it is a Visual Novel Engine, you can make stuff like this: https://f95zone.to/threads/sakura-dungeon-v1-0-5-winged-cloud.997/
I had to use Unity to make my Dungeon Crawler because I do not know Python, but Ren'Py would have been a good option if I did.
At the end choosing the right Game Engine is part of designing the game, suggesting general purpose engines is always a safe guess, but say he wanted to have a Visual Novel Hybrid (like my game), then he'd either need to choose between remaking all the Ren'Py features in Godot or implementing a battle system on Ren'Py.