Need to protect directory..

Hi,

Hoping you could help me! When I first started out, I developed a website on client's hosting account which they brought themselves. Bad move. It's been a few years and now, because they have access to the root directories etc. via cPanel, they have asked a family member to jump in and start meddling with the directories. Looks like he is trying to design another website which will most likely leech off my code.

I absolutely don't want him accessing my code which I spent months, even years, working on! I tried password-protecting the folder in cPanel, but that doesn't stop anyone accessing it if they view it in cPanel's file manager. I need something which will stop direct access unless they have a password.. Or an alternative. Please!!

Thanks.