You've said that you've made 'everyone else' in the family a quilt, but your 39 yr old son. Did you shop from your stash for them as well? The sashing fabric appears to be in the light turquoise family. In order to make sure it looks 'manly' I'd use darker colors, maybe even solid fabrics. Unless your son likes those types of fabrics you've chosen. That being said, no matter what you make his quilt from, it will keep him warm.
I had the ability to ask each immediate family member what they'd like their quilt to be, and they helped pick out the exact colors. That way I knew they'd like it. For some extended family members, I asked what the color scheme was in the room that I was going to be making the quilt for. Otherwise, they helped in picking out the fabric if they wanted a different color. I always picked out a few yards of coordinating fabrics when making every quilt, that way even if the colors they chose weren't my favorites, I still enjoyed piecing and adding my picks too!
Good luck and hopefully you'll post what the finished project looks like for your 39 year old son.