You shouldn't fumble around with the permissions of system folders. Having access to
/etc is pretty vital for many processes, some of which might not run as
root. Simply said: It might be possible, but it's not worth the hassle.
I'd rather encourage you to set up a chroot jail instead.
A chroot jail is the common expression used to describe a section of a filesystem that is sectioned off for a particular user. On a web server, it is particularly useful for the security of shared hosting accounts.
So, you could "lock" the dev in
/var/www – or even a subfolder of that – and let him do all he wants without ever being able to see any directory "above" the one he's locked into.
Building chroot jails is made easy through utilities like Jailkit, or is explained in various blog entries and how-to's, like this one: How to build a chroot jail environment for CentOS