NTA - his ego wrote a check his body couldn’t cash. It’s why the military are supposed to exercise every day, even if it’s light (I served 5 years; wife served 22).
I’ve been in your husband’s shoes; not taking it seriously enough and getting burned when it counted. I regretted it later, and in some respects I still regret it now. Hopefully he’ll use this as self-motivation. If he does, cheer him on. If he doesn’t, let him know that you enjoyed wrestling him last time and smile!