As of now, I would continue to keep him in a soft padded area with feed and water provided. For any superficial injuries, you may dab an antibacterial ointment overtop; with the foot, you may try and soak that in some cool epsom saltwater to reduce some of the swelling going on. A foot bandage may be indicated to provide cushioning to the foot and reduce movement in the joints until a vet can be seen.
Was it just the foot that was crushed? Or is part of the leg involved? I don't have X-ray vision, but I can imagine every bone in his foot crushed into splinters, not to mention the traumatized tissue including ligaments and muscle. A vet visit is definitely called for.
If that isn't an option, you will need to assume the foot is in the condition I painted above - crushed. If no bones have fragmented and punctured the exterior skin, they may heal after a fashion. Same with the crushed tissue. But if the trauma is as severe as I imagine, his body will eventually wall off the injuries, blood flow to the injured tissue will cease, and eventually the foot will fall off.
Be certain that despite his normal seeming behavior, he is in a lot of pain. A vet can X-ray the injured foot and leg and determine the extent of the injuries, and you will be better equipped to make the right decisions for this fellow.
Please take him to a vet. There are a lot of injuries you can treat at home, but this is not one of them. It's likely a crush injury which can't heal on its own. The foot will fall off or go septic if you leave it. He needs antibiotics and pain meds. I can only imagine how badly this must hurt.
Oh good! See if there are any poultry vets in your area, try to find someone who already specializes, and knows how to treat poultry if possible. Most regular vets aren't experienced with poultry, and may not have all the info for treatment. Hope the vet can help!
I think they will put him to sleep. Maybe you can get a diagnosis and estimate and limit loss to an Office Visit, exam and x-rays, by being informed of next steps and their costs? Or you can decide if that path is one you can afford. It's sort of a Livestock vs pet decision...not easy. ..but all of us who have poultry will face the decision.
Maybe collect and try to hatch some of his offspring as a way to remember them, if this is their time to cross the river? Truly sorry about the dilemma.