Oh, nertz. I thought of Urban Outfitters overnight and made a mental note to tell you, Maya, but now I see it's been suggested and nixed. I agree it can be pricey, but (here in the UK at least) it's a mixed bag, and there are often more affordable things, as well. Worth a shot, anyway.
Your friend (a total cutie, by the way!) likely has a hard time because his shoulders look quite broad, compared to his torso. My boyfriend is the same, and even now that he has more money to spend on clothing, it's hard to find shirts that fit in the waist, yet have shoulder seams that aren't too narrow. But he loves clothes shopping, so he doesn't mind the hunt, fortunately. (I do!)
OT- I know what you mean about wanting more "scientific" friends! Literally every one of my friends from uni is a designer or artist of some sort (fashion, graphic design, architecture, illustration, photography, this list goes on). It's such a novelty to me when I get to hang out with my high school friends, who did a lot more varied kinds of things. Like, a bunch of my friends are civil servants now and I love hearing about their jobs... they think I'm crazy, of course.