They're not bell bottoms. They're fairly straight legged jeans. The reason they look so wide at the bottom is because his calves are much smaller than his thighs. I have the same problem with straight leg pants, which is why I normally wear tapered.
https://gamefaqs.gamespot.com/a/forum/8/8f445efe.jpg
https://gamefaqs.gamespot.com/a/forum/a/aef67053.jpg