$10 cash or in SATS?
Discussion
Send it to him in sats. I doubt they will sell if it's a small amount and it gives them some exposure to it. They will probably see it grow over the next year and when the halvening kicks in probably give you a panicked phone call 😁
“Why didn’t you tell me to buy more!! It’s too expensive now!!”
What’s the best wallet in the US to let him spend at a store?
Are people accepting mainchain or lightning? I don't know as I don't live there. But I wouldn't even worry about the spending part you don't want him to spend it yet anyway.... Perhaps exodus is a good one to start with as it does both. Or for small amounts and ease of use just wallet of satoshi.
Later on when he wants to buy the blockchain.com is the easiest to switch from account to a private key wallet. I can send you a referral code if you want to try it out and.you can do the same for him ;)