As for a handrail, a sturdy non-movable shelf at the right level would give him more than enough support for navigating along the sides of a room with his cane.
I'm not quite sure how to explain it, but I'm talking about having a 12'x60' building with zero 'normal' interior walls. Instead, I'd like to have ~9' long floor to ceiling built in storage separating each room and serving as structural supports. The last three feet will be the 'closed' portion of a pocket door, with the 'hidden' portion of the pocket door being tucked into the center of the first three feet of the storage. Each 'wall' can be from 12" ( 6" on each side) to however deep I want - I'm thinking 24" max when I want it to serve as an 18" closet on one side and a 6" bookshelf on the other.
I threw together the world's crappiest sketchup draft here:
The storage unit on the left would be huge - 30" deep - and the one on the right would be 18" deep. Those were just the first two designs I sketched after randomly tossing in bathroom stuff. The design of each unit would be based on the purpose that side of the wall is serving. I really like the one on the right, since the kitchen stuff would be along the back wall of the common room next door. I'd have to think on the one that would be the wall between the bathroom and bedroom. All these would be open - no cabinet doors, few drawers -
Anyway, the more I think on it, I'm asking the wrong stupid question. Obviously it's technically feasible, as long as the storage design is built around any necessary structural components and the pocket door unit. I'm wondering if it's a better solution than having normal interior walls and handling storage and handrails differently. Cost is only a secondary issue in this situation, accessibility and usability are primary. Aesthetics don't matter much, if at all.