I don’t think this happens often, but my best friend in college became my best friend in life . . . . . truly like a brother, and his family became like my second family. We met at orientation the summer before school started, hit it off, became inseparable, and went on to work together.
But we never lived together. We lived in different dorms, and then he moved into his fraternity. I wasn’t in one and moved into an apartment with 3 other guys who I hadn’t spent a lot of time with before moving in together, but the goal was to find people compatible for living together in close quarters, not necessarily being best friends with them. If it works out, great, but you may be in for a letdown if your expectation is to become best friends with your roommate(s). Two of my roommates were best friends in high school, but one ended up to be a challenge for all of us to live with and their friendship became strained after living together.
My best friend from junior high through high school also went to my college, He was the only other guy from my class who did, but we didn’t plan it. It just worked out that way, and we never lived together either. He was heavily involved in athletics, lived with and spent most of his time with his teammates, and we rarely saw each other.
We both went on to different grad schools, but close enough in distance to be able to visit each other for occasional weekends and made a point of doing so. I saw him far more then than I did in undergrad when he was traveling with the team and spending all of his free time training. For many serious college athletes, they really are that busy and it just makes more sense to room with their teammates. If that’s what he does, I wouldn’t take it personally if I were you.
IMO, there’s either a best/close friend connection there that perseveres - or there isn’t. It can’t be forced, and living together isn’t necessarily going to make it happen. It might even result in the opposite.