Ditto what @Tuvalu said. Also keep in mind that it feels like it goes a lot faster than it does. I think it goes around 30mph at its fastest and it doesn't flip or loop at all. I totally get his want for a belt, but you can assure him that the lap bar creates plenty of security.
I wish I could have a seatbelt! Ridden it once, so terrified I've never ridden again (and I was an adult). I just hung on and closed my eyes - yeah I know ...
I always feel like I am going to fly out of rides like that but I just grab onto the bar for dear life. Space Mountain pushes the limits of what I find thrilling and what I find unpleasantly frightening. But I do it once per trip. E:E and ToT crossed that boundary for me so I no longer ride them. RnRC I still like despite the inversions. I agree, seatbelts would be nice though.