Oh yeah, forgot to check that. That seems to be the case, we just checked. He said the game was running at "normal speed" so I assumed he was getting 60FPS but apparently not which makes sense and apparently none of the webgl effects work for him like I thought they did so this is all cleared up now. Thanks.
I was going to give him the Chrome GPU test but he doesn't use Chrome. Oh well, I was thinking of putting a disclaimer at the start of the game where it warns you if you're not running webgl and that the game will probably run much slower.