PHP Fatal error – Site Broken after Theme Update

We appear to have an issue with our website breaking (error 500) after each Enfold Theme Update.

Received from Hosting company:
“Here is the error:
“FastCGI: server “/usr/lib/cgi-bin/php5-fpm” stderr: PHP message:
PHP Fatal error: Can’t use function return value in write context in /web/sites/iadesigns/tln.com/wp-content/themes/enfold/header.php on line 6. We commented out line 6 so the site will load.”

I then asked if this line needs to be commented out after EACH update, they responded “Yes.This is a code issue with the theme. You should reach out to the programmer.”

This is what my programmer tells me:
I think it’s having trouble with: empty( avia_get_option( ‘lightbox_active’ ) )

It doesn’t like receiving a function’s returned value as the parameter for “empty”. It wants a variable, not a function.

I’m thinking the resolve is by adding a new line of code above line 6:
$var_lightbox_active = avia_get_option( ‘lightbox_active’);
which stores the function’s returned value in a variable,

And then modifying the code first mentioned above to read:
empty( $var_lightbox_active )
which uses our new variable instead of a function for the “empty” function’s parameter.

Can you assist with this theme issue? Otherwise we will not be able to update the Theme when needed.