It *is* chicken pox. Shingles is the same virus. After you get chicken pox as a kid, the disease never goes away, but like herpes, hides out in your nervous system to come out again when you're older. It feels worse because in the case of shingles it infects the nerve endings, making them hypersensitive.
If he infects you, you therefore won't get shingles now, you'll get chicken pox. Shingles will come out when you're his age.
If you've been vaccinated for chicken pox you're probably safe, but yeah. He should keep his hands to himself.