One of the best methods of carrying if you have to sit or use crutches is a cross-draw type method.
Positioning the gun toward the front moves it out of the way of the crutches or seat.
Among the methods of carrying are a cross-draw holster either outside or inside the waistband, a fanny pack, or one of the elastic belly bands.
Pocket carry depends entirely on the pants and on how you swing the crutches.
Depending, the crutches may still hit the gun if in a pocket.
The fanny pack has a lot to offer. You can carry the gun, spare ammo, wallet, keys, etc all in one easy to put on package. Since it is all in one package, there's less chance you'll run down to the store and leave the gun at home because it takes time to put on a holster, or even to remember to take the gun at all.
Since the pack is made with it's own belt, you can easily move the pack around on your waist as needed during the day.
A good pack like the Blackhawk 5-5-10 Urban Carry is VERY fast to draw from.
Last, unlike with other people, a fanny pack on a handicapped person is sort of expected and doesn't necessarily say "gun".
If you do pocket carry, a pocket holster is almost required.
A pocket holster prevents so much pocket wear, prevents "printing" the gun, and most important, it positions the gun so it doesn't shift around and wind up out of position for a draw.
In many cases, if you just drop a gun in the pocket, over the day it's going shift around and wind up upside down in the pocket.