Any other ideas or suggestions?
2 tablespoons each of baking soda, arrowroot podwer, and coconut oil. You can add a few drops of essential oil. I did lavender.
I wouldn't recommend baking soda either, until the rash is gone and even then, the BS may cause it to come back. I use just coconut oil (virgin) and it works for the most part, although sometimes not so much. But if he's washing multiple times a day, he could certainly reapply CO a couple of times throughout the day to freshen up too. Of course, it's preferable not to have to do that, but I'd rather do that than have that rash!