If you are worried if he can touch your balance then don't get stressed with it as long as he didn't have your private key or account password and 2FA since he can't withdraw the funds he sent to you. You are the one who can withdraw that so chill out and if you think its time to take that money out of your wallet since you are been stress because you don't know what to do or other factors give you headache much better to withdraw it then exchange to fiat so that you will live comfortably and then just grab new balance to spend on online thing once you learn a lot of things about bitcoin.