Proper mountain climbing jackets have articulated arms. This means they are loads easier to put on when you’re sitting in a wheelchair, especially if you have a limited range of motion in your arms or shoulders. The brand doesn’t matter so much as the articulation, so look for that feature. I have a (now discontinued sadly) Montane climbing jacket (they make Mountain Rescue jackets) and as well as being easier to put on in the chair, it is pretty much totally weatherproof, and plain enough to be unobtrusive. I only wish you could buy suit jackets made out of this material.