Connect the phone to the Mac. Use the file browser Mac provides (the last time I touched a Mac it was called finder, and the year was 1985, so I don't know what program you use in a Mac today to delete files). Go to the phone (it should show as a drive - make sure you have USB set as MTP, not as Charge) and find and delete the files.
I have to warn you, though - with some PC-phone combinations (and by PC I mean any OS - Mac, Windows, Linux) it can take an hour to delete 10 files, where doing it with a file manager app in the phone takes seconds. Maybe list the files, using ls (does Mac use that?) in a terminal, redirecting the output to a file, then write a shell script from the contents of the file deleting the files you want (and do a ping after each one to force a fake "wait" - USB clogs up on mass file operations done quickly) - if you know how to write a shell script in Mac. (If you don't, now would be a great time to learn - the knowledge comes in handy for so many things you think will take you a monumental amount of effort, when you can do it in a minute by writing a shell script.)