Like people's hair, dog's coats vary. Some have short or long fine silky hair while others have coarser hair.
From what I understand, the white hairs on a Boxer will usually be softer than the colored hairs, and in my limited experience, this seems to be the case. But Indy's hair (he's a plain brindle) is softer than his sister/cousin Ava's hair and she is white, with the exception of their heads. The hair on Ava's head is softer and smoother to the touch.
If you want to try a supplement that added shine to your pups coat, add a 1000mg capsule of fish oil concentrate to his diet. You can get a 300 tablet of the fish oil concentrate with Omega 3 fatty acids at BJ's wholesale club for less than ten dollars. Some will give a fish oil tablet in the morning and a flax seed oil tablet in the afternoon or evening, or vice versa.
If you don't have a BJ's near you, try Walmart or a similar discount store. The prices should be similar.
We started giving Indy and Ava the fish oil concentrate with their evening meal over a year ago, and both of their coats got noticeably softer and shinier. The real bonus however is that it dramatically reduced their shedding.
Both of their coats were fine to begin with. Ava has always shed more than Indy, though they both shed less than our first Boxer, Rocky. Of course, with Ava being white, her hairs are more noticable on everything except for very light clothing, upholstery, and bedspreads.
When we used to pet Rocky, it was like raking a lawn, the loose hairs would accumulate at the end of each stroke. He had an extremely shiny coat consisting or long coarse hairs.
The oil tablets have other health benefits in addition to improving their coats. It costs us about five or six cents per day for the two tablets they get.
Tom