Read_Only permission - plus diagnose commands

Hi guys,

I've one customer that needs read-only access to the fortigate, 

all works fine when I set up the "Administrator Profile" with read-only permission.

now my customer want to launch the "diagnose sniffer packet" command on the CLI, 

but is not possible with such permissions

is there a way to give him these kind of commands, without give him too many read-write permissions?

thanks so much