I would give him penicillin for sure. I use to soak but switched to drawing salve. use drawing salve on a gauze pad to cover the area completely. Goop it on there. Then i wrap it up with vetwrap for a couple days. Take it off & find the scab & you should be able to gently pull the corn out completely. He will feel much better then. I spray vetericyn and use blue butter or neosporin without pain relief & wrap back up for a day or two. I have a rooster with the same thing going on but there's no scabs like with bumblefoot now but still swollen and he doesn't walk on it much. I've giving him antibiotics and kept him inside while treating BF but I'm at a loss as what to do now. Good luck with your guy!