So, I looked around on the web, and found this company JKaye Designs (actually, a one-lady shop) that makes colorful surgeons caps. Yesterday, he showed up at the clinic wearing a cap in this pattern:
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I wore one with multiple Snoopy characters on it, but unfortunately it's out of stock, so I don;t have a picture. And the Unknown Daughter has this one on order:
Unfortunately, we can't convince the Unknown Wife to wear one.
In any event, if you know anyone undergoing chemo who wants to dress up their noggin, give JKaye Designs some business. A small one fits a kid pretty well.