Not that you don't love his normal ensemble of basketball shorts and free work t-shirts but he could use a few fashion upgrades. Once he starts getting compliments he'll realize what a fashion genius you are and he'll stop making fun of your skinny jeans!
1. Replace solid sport dress shirts with a pattern - for instance stripes or a small check. Some nice color combinations: light blue and white, and gray or khaki with black.
2. Striped ties, in all kinds of colors, are back, so grab a handful.
3. Ditch the pleated pants and get him into a pair of flat-fronts; they're sexy and stylish.
4. Invest in a casual suit - say, for this time of year, a linen one in a shade of brown, blue, or gray.
5. Replace his raincoat with a newly fashionable three-quarter-length coat that hits just above or below the knee.