I'm certain that you or your kids have a few medals around. Simply take the medal off the neck ribbon (or keyring), put it on an ornament hook, and hang it on your tree!
Here's a year-round option: buy an ornament "tree" to showcase your medals. The ornament holders come in many shapes and sizes and don't have to be a "tree". This would work for kids or adults. I picture it particularly on a desk or a shelf. Something like these:
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