I would think so. Its a localized infection, not systemic, and the bird is healthy enough to be spurring you, so it can't be too sick.
And, I assume you would fully cook it to an internal thigh temperature of 180 as per current food safety guidelines, so no bacteria could possibly survive that.
I think the bigger risk, albeit slight, would be if you were to come in contact with the bacteria from the infection during butchering, through a cut or open sore. Whether or not the bacteria causing the infection can be passed to humans is very hard to say, but I wouldn't want to take chances.
I guess if it were me, I wouldn't be afraid to use it, I would probably just take something that could be used as a tourniquet of sorts and tie off the leg just above the knee joint as soon as I killed the bird, then immediately remove the leg below the tourniquet and discard the infected foot before proceeding with plucking and butchering the rest of it. That way, none of the bacteria from the infection should be getting into or onto the rest of the meat. Also, be sure to disinfect your hands and tools after cutting off the bad foot and before proceeding with the rest of the butchering process.
The last thing I would do would be to soak the carcass in salted water with a bit of apple cider vinegar for an hour or so at some point -- we do that with all of our poultry, it seems to draw a lot of the impurities from the meat, or at least, it does something, because the water gets quite nasty looking after that time, and all of that is rinsed down the drain.
Good luck. I'm sure it will be fine and he'll taste good.
