Sure take it. No way the promoters would get anyone paying to see it, but I'd take a concussion for $100k this year, especially if it's USD, if it isn't strictly boxing I might not get completely destroyed in the ground game.
That depends. Take it, if the alternative is they go on to have an unhealthy, miserable life, but I see them?
Or could they still have a healthy, happy life and me be in it? In which case, leave it.