The climb out of Kash is steep heading toward Joyce, the rest of the way is rough in spots and muddy too.
The Brent area has some rough patches as well. I think considering he doesn't need anymore stress on his injured ankle, I would opt for 2 walking sticks with the carbide tips for traction up/down the steep areas.
With the wrist straps, he would have  better grip than with paddles IF he stumbled. CAMPMOR sells their own brand, for about $50 a set. You could use for other outdoor activities and might be worth a look.